PHY 121 FINAL EXAM REVIEW

Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Just as they reach the lake below

A) the speed of Alice is larger than that of Tom.
B) the speed of Tom will always be 9.8 m/s larger than that of Alice.
C) the speed of Alice will always be 25 m/s larger than that of Tom.
D) they will both have the same speed.
E) the splashdown speed of Alice is larger than that of Tom.

A) the speed of Alice is larger than that of Tom.

You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts on the bat is

A) greater than 1500 N if the bat bounces back.
B) exactly 1500 N whether or not the box moves.
C) exactly 1500 N only if the box does not move.
D) less than 1500 N if the box moves.
E) greater than 1500 N if the box moves.

B) exactly 1500 N whether or not the box moves.

Suppose that a car traveling to the west (the -x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration in the x direction is correct?

A) Its acceleration is positive but its velocity is negative.

B)Both its acceleration and its velocity are negative.

C)Its acceleration is negative but its velocity is positive.

D)Both its acceleration and its velocity are positive.

A) Its acceleration is positive but its velocity is negative.

The motion of a particle is described in the velocity versus time graph shown in the figure. We can say that its speed

A) decreases.
B) increases.
C) decreases and then increases.
D) increases and then decreases.

C) decreases and then increases.

The figure shows the velocity of a particle as it travels along the x-axis. What is the direction of the acceleration at t = 0.5 s?

A) in the +x direction
B) in the -x direction
C) The acceleration is zero.

B) in the -x direction

For general projectile motion, when the projectile is at the highest point of its trajectory?

A) its acceleration is zero.
B) the horizontal and vertical components of its velocity are zero.
C) its velocity is perpendicular to the acceleration.
D) its velocity and acceleration are both zero.
E) the horizontal component of its velocity is zero.

C) its velocity is perpendicular to the acceleration.

Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Compare the time it takes each of them to reach the lake below.

A) Alice and Tom will reach the surface of the lake at the same time.
B) Tom reaches the surface of the lake first.
C) Alice reaches the surface of the lake first.

A) Alice and Tom will reach the surface of the lake at the same time.

A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will

A) be behind the package.
B) be in front of the package.
C) depend of the speed of the plane when the package was released.
D) be over the package.

D) be over the package.

While an object is in projectile motion (with upward being positive) with no air resistance

A) the vertical component of both its velocity and its acceleration remain constant.
B) the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to -g.
C) the horizontal component of its velocity remains constant and the horizontal component of its acceleration is equal to -g.
D) the vertical component of its velocity remains constant and the vertical component of its acceleration is equal to -g.
E)the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to zero.

B) the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to -g.

An object is moving to the right, and experiencing a net force that is directed to the right. The magnitude of the force is decreasing with time. The speed of the object is

A) constant in time.
B) increasing.
C) decreasing.

B) increasing.

You are standing in a moving bus, facing forward, and you suddenly fall forward as the bus comes to an immediate stop. The force that pushes forward on you as the bus stops is

A) the force of gravity.
B) the force due to kinetic friction between you and the floor of the bus.
C) the normal force due to your contact with the floor of the bus.
D) the force due to static friction between you and the floor of the bus.
E) No forward force is acting on you as the bus stops.

E) No forward force is acting on you as the bus stops.

Consider what happens when you jump up in the air. Which of the following is the most accurate statement?

A) You are able to spring up because the earth exerts a force upward on you that is greater than the downward force you exert on the earth.
B) When you jump up the earth exerts a force F1 on you and you exert a force F2 on the earth. You go up because F1 > F2.
C) Since the ground is stationary, it cannot exert the upward force necessary to propel you into the air. Instead, it is the internal forces of your muscles acting on your body itself that propels your body into the air.
D) When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air.
E) It is the upward force exerted by the ground that pushes you up, but this force cannot exceed your weight.

D) When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air.

A stalled car is being pushed up a hill at constant velocity by three people. The net force on the car is

A) down the hill and equal to the weight of the car.
B) zero.
C) up the hill and greater than the weight of the car.
D) up the hill and equal to the weight of the car.
E) down the hill and greater than the weight of the car.

B) zero.

A box of mass m is pulled with a constant acceleration a along a horizontal friction less floor by a wire that makes an angle of 15° above the horizontal. If T is the tension in this wire, then

A) T > ma.

B) T = ma.

C) T < ma.

A) T > ma.

A 615 N student standing on a scale in an elevator notices that the scale reads 645 N. From this information, the student knows that the elevator must be moving...

A)upward.
B) downward.
C) You cannot tell if it is moving upward or downward.

C) You cannot tell if it is moving upward or downward.

Which one of the following free-body diagrams best represents the free-body diagram, with correct relative force magnitudes, of a person in an elevator that is traveling upward but is gradually slowing down at a rate of 9 m/s^2? F⃗ f is the force of the floor on the person and F⃗ g is the force of gravity on the person

D

An object is hanging by a string from the ceiling of an elevator. The elevator is slowing down while moving upward. What is the magnitude of the tension in the string?

A) The tension in the string is zero.
B) The magnitude of the tension in the string is less than the magnitude of the weight of the object.
C) The magnitude of the tension in the string is greater than the magnitude of the weight of the object.
D) The magnitude of the tension in the string is equal to the magnitude of the weight of the object.
E) The tension in the string cannot be determined without knowing the speed of the elevator.

B) The magnitude of the tension in the string is less than the magnitude of the weight of the object.

Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined plane and allowed to slide down from rest.
A) It takes the heavier object 5 times longer to reach the bottom of the incline than the lighter object.
B) It takes the lighter object 10 times longer to reach the bottom of the incline than the heavier object.
C) It takes the heavier object 10 times longer to reach the bottom of the incline than the lighter object.
D) It takes the lighter object 5 times longer to reach the bottom of the incline than the heavier object.
E) The two objects reach the bottom of the incline at the same time.

E) The two objects reach the bottom of the incline at the same time.

A packing crate is sitting at rest on an inclined loading ramp. How does the magnitude of the force of static friction compare to the other forces acting on the crate?

A) The magnitude of the force of static friction is equal to the magnitude of the component of the weight of the crate perpendicular to the inclined ramp.
B) The force of static friction is the only force acting on the crate, and it is responsible for keeping the crate at rest.
C) The magnitude of the force of static friction is equal to the magnitude of the normal force acting on the crate.
D) The magnitude of the force of static friction is equal to the magnitude of the weight of the crate.
E) The magnitude of the force of static friction is equal to the magnitude of the component of the weight of the crate parallel to the inclined ramp.

E) The magnitude of the force of static friction is equal to the magnitude of the component of the weight of the crate parallel to the inclined ramp.

If a force always acts perpendicular to an object's direction of motion, that force cannot change the object's kinetic energy.

A) True
B) False

A) True

Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. When they hit the ground

A) the heavier one will have twice the kinetic energy of the lighter one.
B) the heavier one will have four times the kinetic energy of the lighter one.
C) both of them will have the same kinetic energy.
D) the heavier one will have 2√ times the kinetic energy of the lighter one.

A) the heavier one will have twice the kinetic energy of the lighter one.

If the net work done on an object is positive, what can you conclude about the object's motion?

A) The object is at rest; its position is constant.
B) The object is speeding up.
C) The object is moving with a constant velocity.
D) The object is slowing down.

B) The object is speeding up.

A girl throws a stone from a bridge. Consider the following ways she might throw the stone. The speed of the stone as it leaves her hand is the same in each case, and air resistance is negligible. Case A: Thrown straight up.Case B: Thrown straight down.Case C: Thrown out at an angle of 45° above horizontal. Case D: Thrown straight out horizontally. Case E: The speed will be the same in all cases.In which case will the speed of the stone be greatest when it hits the water below?

A) Case A
B) Case B
C) Case C
D) Case D
E) The speed will be the same in all cases.

E) The speed will be the same in all cases.

Block 1 and block 2 have the same mass, m, and are released from the top of two inclined planes of the same height making 30° and 60° angles with the horizontal direction, respectively. If the coefficient of friction is the same in both cases, which of the blocks is going faster when it reaches the bottom of its respective incline?

A) Both blocks have the same speed at the bottom.
B) Block 2 is faster.
C) We must know the actual masses of the blocks to answer.
D) Block 1 is faster.
E) There is not enough information to answer the question because we do not know the value of the coefficient of kinetic friction.

B) Block 2 is faster.

Two stones, one of mass m and the other of mass 2m, are thrown directly upward with the same velocity at the same time from ground level and feel no air resistance. Which statement about these stones is true?

A) At their highest point, both stones will have the same gravitational potential energy because they reach the same height.
B) At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy.
C) The lighter stone will reach its maximum height sooner than the heavier one.
D) The heavier stone will go twice as high as the lighter one because it initially had twice as much kinetic energy.
E) Both stones will reach the same height because they initially had the same amount of kinetic energy.

B) At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy.

Two identical balls are thrown directly upward, ball A at speed v and ball B at speed 2v, and they feel no air resistance. Which statement about these balls is correct?

A) At its highest point, ball B will have twice as much gravitational potential energy as ball A because it started out moving twice as fast.
B) Ball B will go four times as high as ball A because it had four times the initial kinetic energy.
C) Ball B will go twice as high as ball A because it had twice the initial speed.
D) At their highest point, the acceleration of each ball is instantaneously equal to zero because they stop for an instant.
E) The balls will reach the same height because they have the same mass and the same acceleration.

B) Ball B will go four times as high as ball A because it had four times the initial kinetic energy.

A potential energy function for system 1 is given by U1(x)=Cx2+Bx3. The potential energy function for system 2 is given by U2(x)=A+Cx2+Bx3, where A is a positive quantity. How does the force on system 1 relate to the force on system 2 at a given position?

A) The force on the two systems will be in opposite directions.
B) The force is identical on the two systems.
C) There is no relationship between the forces on the two systems.
D) The force on the second system will be with greater than the force on the first system.
E) The force on the second system will be with less than the force on the first system.

B) The force is identical on the two systems.

Two identical balls are thrown vertically upward. The second ball is thrown with an initial speed that is twice that of the first ball. How does the maximum height of the two balls compare?

A) The maximum height of the second ball is four times that of the first ball.
B) The maximum height of the second ball is two times that of the first ball.
C) The maximum height of the second ball is eight times that of the first ball.
D) The maximum heights of the two balls are equal.The maximum height of the second ball is 1.41 times that of the first ball.

A) The maximum height of the second ball is four times that of the first ball.

A ball drops some distance and gains 30 J of kinetic energy. Do NOT ignore air resistance. How much gravitational potential energy did the ball lose?

A) exactly 30 J
B) less than 30 J
C) more than 30 J

C) more than 30 J

A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring

A) the heavier block will have more kinetic energy than the lighter block.both blocks will both have the same amount of kinetic energy.
B) the lighter block will have more kinetic energy than the heavier block.
C) the magnitude of the momentum of the heavier block will be greater than the magnitude of the momentum of the lighter block.
D) both blocks will have equal speeds.

B) the lighter block will have more kinetic energy than the heavier block.

When a constant force acts on an object, what does the object's change in momentum depend upon?
Check all that apply.

A) The change in momentum depends upon the change in the velocity of the object.
B) The change in momentum depends upon the time interval during which the force acts.
C) The change in momentum depends upon the magnitude of the force.
D) The change in momentum depends upon the change in the position of the object.
E) The change in momentum depends upon the mass of the object.

A) The change in momentum depends upon the change in the velocity of the object.
B) The change in momentum depends upon the time interval during which the force acts.
C) The change in momentum depends upon the magnitude of the force.
E) The change in momentum depends upon the mass of the object.

In a perfectly ELASTIC collision between two perfectly rigid objects

A) the kinetic energy of each object is conserved.the momentum of each object is conserved.
B) the kinetic energy of the system is conserved, but the momentum of the system is not conserved.
C) both the momentum and the kinetic energy of the system are conserved.
D) the momentum of the system is conserved but the kinetic energy of the system is not conserved.

C) both the momentum and the kinetic energy of the system are conserved.

A lump of putty and a rubber ball have equal mass. Both are thrown with equal speed against a wall. The putty sticks to the wall. The ball bounces back at nearly the same speed with which it hit the wall. Which object experiences the greater momentum change?

A) Not enough information is given to determine the answer.
B) The ball experiences the greater momentum change.
C) The putty experiences the greater momentum change.
D) They both experience the same momentum change.

B) The ball experiences the greater momentum change.

In an INELASTIC collision between two objects

A) the kinetic energy of the system is conserved, but the momentum of the system is not conserved.
B) the momentum of each object is conserved.
C) the kinetic energy of each object is conserved.
D) the momentum of the system is conserved but the kinetic energy of the system is not conserved.
E) both the momentum and the kinetic energy of the system are conserved.

D) the momentum of the system is conserved but the kinetic energy of the system is not conserved.

A small glider is coasting horizontally when suddenly a very heavy piece of cargo falls out of the bottom of the plane. You can neglect air resistance. Just after the cargo has fallen out

A) the plane speeds up and the cargo slows down.
B) the plane speeds up but the cargo does not change speed.
C) both the cargo and the plane speed up.
D) neither the cargo nor the plane change speed.
E) the cargo slows down but the plane does not change speed.

D) neither the cargo nor the plane change speed.

A girl and a boy are riding on a merry-go-round that is turning at a constant rate. The girl is near the outer edge, and the boy is closer to the center. Who has greater linear speed?

A) The boy has greater linear speed.
B) The girl has greater linear speed.
C) Both the girl and the boy have zero linear speed.
D) Both the girl and the boy have the same nonzero linear speed.

B) The girl has greater linear speed.

A girl and a boy are riding on a merry-go-round that is turning at a constant rate. The girl is near the outer edge, and the boy is closer to the center. Who has greater tangential acceleration?

A) Both the girl and the boy have the same nonzero tangential acceleration.
B) Both the girl and the boy have zero tangential acceleration.
C) The girl has greater tangential acceleration.
D) The boy has greater tangential acceleration.

B) Both the girl and the boy have zero tangential acceleration.

A slender uniform rod 100.00 cm long is used as a meter stick. Two parallel axes that are perpendicular to the rod are considered. The first axis passes through the 50-cm mark and the second axis passes through the 30-cm mark. What is the ratio of the moment of inertia through the second axis to the moment of inertia through the first axis?

A) I2/I1 = 2.3
B) I2/I1 = 1.5
C) I2/I1 = 2.1
D) I2/I1 = 1.9
E) I2/I1 = 1.7

B) I2/I1 = 1.5

A uniform solid sphere has a moment of inertia I about an axis tangent to its surface. What is the moment of inertia of this sphere about an axis through its center?

A) 3/5 I
B) 2/7 I
C) 2/5 I
D) 1/7 I
E) 7/5 I

B) 2/7 I

When a rigid body rotates about a fixed axis, all the points in the body have the same

A) linear displacement.
B) angular acceleration.
C) tangential speed.
D) centripetal acceleration.
E) tangential acceleration.

B) angular acceleration.

A horizontal disk rotates about a vertical axis through its center. Point P is midway between the center and the rim of the disk, and point Q is on the rim. If the disk turns with constant angular velocity, which of the following statements about it are true? (There may be more than one correct choice.)
Check all that apply.

A) The angular velocity of Q is twice as great as the angular velocity of P.
B) The linear acceleration of P is twice as great as the linear acceleration of Q.
C) P and Q have the same linear acceleration.
D) The linear acceleration of Q is twice as great as the linear acceleration of P.
E) Q is moving twice as fast as P.

D) The linear acceleration of Q is twice as great as the linear acceleration of P.
E) Q is moving twice as fast as P.

Starting from rest, a solid sphere rolls without slipping down an incline plane. At the bottom of the incline, what does the angular velocity of the sphere depend upon?
Check all that apply.

A) The angular velocity depends upon the length of the incline.
B) The angular velocity depends upon the radius of the sphere.
C) The angular velocity depends upon the mass of the sphere.
D) The angular velocity depends upon the height of the incline.

B) The angular velocity depends upon the radius of the sphere.
D) The angular velocity depends upon the height of the incline.

Two equal forces are applied perpendicular to a door. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Which force exerts the greater torque?

A) Both forces exert zero torques.
B) The force applied at the midpoint of the door exerts the greater torque.
C) Both forces exert equal nonzero torques.
D) The force applied at the doorknob exerts the greater torque.

D) The force applied at the doorknob exerts the greater torque.

Consider a uniform solid sphere of radius R and mass M rolling without slipping. Which form of its kinetic energy is larger, translational or rotational?

A) Its translational kinetic energy is larger than its rotational kinetic energy.
B) Its rotational kinetic energy is larger than its translational kinetic energy.
C) Both forms of energy are equal.
D) You need to know the speed of the sphere to tell.

A) Its translational kinetic energy is larger than its rotational kinetic energy.

The figure shows the position of an object (moving along a straight line) as a function of time. Assume two significant figures in each number. Which of the following statements about this object is true over the interval shown?

A) The object is accelerating to the left.
B) The object is accelerating to the right.
C) The average speed of the object is 1.0 m/s.
D) The acceleration of the object is in the same direction as its velocity.

A) The object is accelerating to the left.

Which one of the following graphs could possibly represent the vertical position as a function of time for an object in free fall from t=0 ?

B

Shown below are the velocity and acceleration vectors for a person in several different types of motion. In which case is the person slowing down and turning to his right?

B

A figure skater rotating at 5.00 rad/s with arms extended has a moment of inertia of 2.25 kg·m2. If the arms are pulled in so the moment of inertia decreases to 1.80 kg·m2, what is the final angular speed?

A) 1.76 rad/s
B) 6.25 rad/s
C) 2.25 rad/s
D) 0.810 rad/s
E) 4.60 rad/s

B) 6.25 rad/s

A constant net torque is applied to a rotating object. Which of the following best describes the object's motion?

A) The object will rotate with constant angular velocity.
B) The object will rotate with constant angular acceleration.
C) The object will rotate with increasing angular acceleration.
D) The object will have a decreasing moment of inertia.
E) The object will rotate with decreasing angular acceleration.
F) The object will have an increasing moment of inertia.

B) The object will rotate with constant angular acceleration.

A dumbbell-shaped object is composed by two equal masses, m, connected by a rod of negligible mass and length r. If I 1 is the moment of inertia of this object with respect to an axis passing through the center of the rod and perpendicular to it and I 2 is the moment of inertia with respect to an axis passing through one of the masses, it follows that

A) I 1 = I 2

B) I 2 > I 1

C) I 1 > I 2.

B) I 2 > I 1

Two weights are connected by a mass less wire and pulled upward with a constant speed of 1.50 m/s by a vertical pull P. The tension in the wire is T (see figure). Which one of the following relationships between T and P must be true?

A)T > P

B) T = P

C) P = T + 100 N

D) P + T = 125 N

E) P = T + 25 N

E) P = T + 25 N

Which one of the following free-body diagrams best represents the free-body diagram, with correct relative force magnitudes, of a person in an elevator that is traveling upward with an unchanging velocity? F⃗ f is the force of the floor on the person and F⃗ g is the force of gravity on the person.

D

Two bodies P and Q on a smooth horizontal surface are connected by a light cord. The mass of P is greater than that of Q. A horizontal forceF⃗ (of magnitude F) is applied to Q as shown in the figure, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P will be

A) less than F but not zero.

B) zero.

C) greater than F.

D) equal to F.

A) less than F but not zero.

Two objects having masses m1 and m2 are connected to each other as shown in the figure and are released from rest. There is no friction on the table surface or in the pulley. The masses of the pulley and the string connecting the objects are completely negligible. What must be true about the tension T in the string just after the objects are released?

A) T = m 1g

B) T < m 2g

C) T = m 2g

D) T > m 2g

E) T > m 1g

B) T < m 2g

Suppose you are playing hockey on a new-age ice surface for which there is no friction between the ice and the hockey puck. You wind up and hit the puck as hard as you can. After the puck loses contact with your stick, the puck will

A) speed up a little, and then slow down.
B) speed up a little, and then move at a constant speed.
C) start to slow down.
D) not slow down or speed up.

D) not slow down or speed up.

A ball is tossed vertically upward. When it reaches its highest point (before falling back downward)

A) the velocity, acceleration, and the force of gravity on the ball all reverse direction.
B) the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is directed downward.
C) the velocity and acceleration reverse direction, but the force of gravity on the ball remains downward.
D) the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward.
E) the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is zero.

D) the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward.

A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of −2.0 m/s. What is the velocity of the two balls after the elastic collision?

A)The velocity of the red ball is +3.0 m/s; the velocity of the yellow ball is −2.0 m/s.
B) The velocity of the red ball is −3.0 m/s; the velocity of the yellow ball is +2.0 m/s.
C) The velocity of the red ball is +2.0 m/s; the velocity of the yellow ball is −3.0 m/s.
D) The red ball stops immediately, and the yellow ball has a velocity of +1 m/s.
E) The velocity of the red ball is −2.0 m/s; the velocity of the yellow ball is +3.0 m/s.
F) The yellow ball stops immediately, and the red ball has a velocity of −1 m/s.

E) The velocity of the red ball is −2.0 m/s; the velocity of the yellow ball is +3.0 m/s.

In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after are given. The collision is

A) perfectly elastic.
B) completely inelastic.
C) partially inelastic.
D) characterized by an increase in kinetic energy.
E) not possible because momentum is not conserved.

A) perfectly elastic.

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force?

A) hitting the brick wall
B)hitting the other car
C) The force would be the same in both cases.
D) We cannot answer this question without more information.
E) None of these is true.

C) The force would be the same in both cases

In a lab environment, you are investigating the impulse of a force exerted on a brick when the brick's speed is reduced from 2.5 m/s to a complete stop. First, you allow the brick to slam into a secured piece of wood, bringing the brick to a sudden stop. Second, you allow the brick to plow into a large slab of gelatin so that the brick comes to a gradual halt. In which situation is there a greater impulse of the force on the brick?

A) There is a greater impulse of the force on the brick from the gelatin.
B) The impulse is the same in both situations.
C) Not enough information is given to determine the answer.
D) There is a greater impulse of the force on the brick from the wall.

B) The impulse is the same in both situations.

In order to get an object moving, you must push harder on it than it pushes back on you.

A) True
B) False

B) False

If an object travels at a constant speed in a circular path, the acceleration of the object is...

A) in the opposite direction of the velocity of the object.
B) in the same direction as the velocity of the object.
C) larger in magnitude the smaller the radius of the circle.
D) zero.
E) smaller in magnitude the smaller the radius of the circle.

C) larger in magnitude the smaller the radius of the circle.

Point P in the figure indicates the position of an object traveling at constant speed clockwise around the circle. Which arrow best represent the direction the object would travel if the net external force on it were suddenly reduced to zero?

A) north west

B) north east

C) south west

D) west

E) south east

E) south east

Point P in the figure indicates the position of an object traveling at constant speed clockwise around the circle. Which arrow best represents the direction of the acceleration of the object at point P?

A) west
B) southwest
C) northeast
D) southeast
E) northwest

B) southwest

A box of mass m is pressed against (but is not attached to) an ideal spring of force constant k and negligible mass, compressing the spring a distance x. After it is released, the box slides up a friction less incline as shown in the figure and eventually stops. If we repeat this experiment but instead compress the spring a distance of 2x

A) just as it moves free of the spring, the box will have twice as much kinetic energy as before.\

B) just as it moves free of the spring, the box will be traveling four times as fast as before.

C) just before it is released, the box has twice as much elastic potential energy as before.

D) the box will go up the incline twice as high as before.

E) just as it moves free of the spring, the box will be traveling twice as fast as before.

E) just as it moves free of the spring, the box will be traveling twice as fast as before.

An object moves in a circular path at a constant speed. What is the relationship between the directions of the object's velocity and acceleration vectors?

A) The velocity vector points in a direction tangent to the circular path.The acceleration is zero.
B) The velocity and acceleration vectors are perpendicular.
C) The velocity and acceleration vectors point in opposite directions.
D) The velocity and acceleration vectors point in the same direction.
E) The velocity vector points toward the center of the circular path. The acceleration is zero.

B) The velocity and acceleration vectors are perpendicular.

A box of mass m is pressed against (but is not attached to) an ideal spring of force constant k and negligible mass, compressing the spring a distance x. After it is released, the box slides up a friction less incline as shown in the figure and eventually stops. If we repeat this experiment with a box of mass 2m

A) just as it moves free of the spring, the heavier box will have twice as much kinetic energy as the lighter box.

B) the lighter box will go twice as high up the incline as the heavier box.

C)both boxes will reach the same maximum height on the incline.

D) both boxes will have the same speed just as they move free of the spring.

E) just as it moves free of the spring, the lighter box will be moving twice as fast as the heavier box.

B) the lighter box will go twice as high up the incline as the heavier box.

The plot in the figure shows the potential energy of a particle, due to the force exerted on it by another particle, as a function of distance. At which of the three points labeled in the figure is the magnitude of the force on the particle greatest?

A) point X
B) point Y
C) point Z

A) point X

A 4.0-kg object is moving with speed 2.0 m/s. A 1.0-kg object is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?

A) the 4.0-kg object
B) the 1.0-kg object
C) Both objects travel the same distance.
D) It is impossible to know without knowing how long each force acts.

C) Both objects travel the same distance.

A graph depicts force versus position. What represents the work done by the force over the given displacement?

A) The work done is equal to the area under the curve.
B) The work done is equal to length of the curve.
C) The work done is equal to the slope of the curve.
D) The work done is equal to the product of the maximum force times the maximum position.
E) Work cannot be determined from this type of graph.

A) The work done is equal to the area under the curve.

A heavy boy and a lightweight girl are balanced on a massless seesaw. The boy moves backward, increasing his distance from the pivot point. What happens to the seesaw?

A) Nothing; the seesaw will remain balanced.
B) The side the girl is sitting on will tilt downward.
C) It is impossible to predict without knowing additional information.
D) The side the boy is sitting on will tilt downward.

D) The side the boy is sitting on will tilt downward.

A girl moves quickly to the center of a spinning merry-go-round, traveling along the radius of the merry-go-round. Which of the following statements are true?
Check all that apply.

A) The angular speed of the system remains constant.
B) The moment of inertia of the system decreases.
C) The angular speed of the system increases.
D) The angular speed of the system decreases.
E) The moment of inertia of the system increases.
F) The moment of inertia of the system remains constant.

B) The moment of inertia of the system decreases.
C) The angular speed of the system increases.

A uniform disk, a uniform hoop, and a uniform solid sphere are released at the same time at the top of an inclined ramp. They all roll without slipping. In what order do they reach the bottom of the ramp?

A) sphere, hoop, disk
B) hoop, sphere, disk
C) hoop, disk, sphere
D) disk, hoop, sphere
E) sphere, disk, hoop

E) sphere, disk, hoop

A heavy boy and a lightweight girl are balanced on a massless seesaw. If they both move forward so that they are one-half their original distance from the pivot point, what will happen to the seesaw? Assume that both people are small enough compared to the length of the seesaw to be thought of as point masses.

A) It is impossible to say without knowing the masses.
B) It is impossible to say without knowing the distances.
C) The side the girl is sitting on will tilt downward.
D) Nothing will happen; the seesaw will still be balanced.
E) The side the boy is sitting on will tilt downward.

D) Nothing will happen; the seesaw will still be balanced.

A nonuniform, 80.0-g, meterstick balances when the support is placed at the 51.0-cm mark. At what location on the meterstick should a 5.00-g tack be placed so that the stick will balance at the 50.0 cm mark?

A) 66.0 cm
B) 35.0 cm
C) 67.0 cm
D) 16.0 cm
E) 34.0 cm

E) 34.0 cm

Planet Z-34 has a mass equal to 1/3 that of Earth, a radius equal to 1/3 that of Earth, and an axial spin rate 1/2 that of Earth. With g representing, as usual, the acceleration due to gravity on the surface of Earth, the acceleration due to gravity on the surface of Z-34 is

A) g/3.

B) 3g.

C) 9g.

D) 6g.

E) g/9.

B) 3g.

Two planets, planet A and planet B, have the same surface gravity. However, planet B has twice the radius of planet A. How does the mass of planet B compare to the mass of planet A?

A) The mass of planet B is four times the mass of planet A.
B) The mass of planet B is twice the mass of planet A.
C) The mass of planet B is one-half the mass of planet A.
D) The mass of planet B is one-fourth the mass of planet A.
E) The mass of planet B is equal to the mass of planet A.

A) The mass of planet B is four times the mass of planet A.

A satellite is orbiting the earth. If a payload of material is added until it doubles the satellite's mass, the earth's pull of gravity on this satellite will double but the satellite's orbit will not be affected.

A) True
B) False

A) True

If we double only the amplitude of a vibrating ideal mass-and-spring system, the mechanical energy of the system

A) increases by a factor of 4.
B) increases by a factor of 3.
C) increases by a factor of 2√.
D) increases by a factor of 2.
E) does not change.

A) increases by a factor of 4.

A restoring force of magnitude F acts on a system with a displacement of magnitude x. In which of the following cases will the system undergo simple harmonic motion?

A) F ∝ x

B) F ∝ sin x

C) F ∝ x^2

D) F ∝ √x

E) F ∝ 1/x

A) F ∝ x

A friction less pendulum released from 65 degrees with the vertical will vibrate with the same frequency as if it were released from 5 degrees with the vertical because the period is independent of the amplitude and mass.

A) True
B) False

B) False

A 30.0-kg child sits on one end of a long uniform beam having a mass of 20.0 kg, and a 40.0-kg child sits on the other end. The beam balances when a fulcrum is placed below the beam a distance 1.10 m from the 30.0-kg child. How long is the beam?

A) 2.12 m
B) 2.07 m
C) 2.20 m
D) 1.98 m
E) 1.93 m

D) 1.98 m

Two planets having equal masses are in circular orbit around a star. Planet A has a smaller orbital radius than planet B. Which statement is true?

A) Planet A has more kinetic energy, more potential energy, and more mechanical energy (potential plus kinetic) than planet B.
B) Planet A and planet B have the same amount of mechanical energy (potential plus kinetic).
C) Planet A has more kinetic energy, less potential energy, and more mechanical energy (potential plus kinetic) than planet B.
D) Planet A has more kinetic energy, less potential energy, and less mechanical energy (potential plus kinetic) than planet B.

D) Planet A has more kinetic energy, less potential energy, and less mechanical energy (potential plus kinetic) than planet B.

Why does a satellite in a circular orbit travel at a constant speed?

A) The net force acting on the satellite is zero.
B) There is no component of force acting along the direction of motion of the satellite.
C) There is a force acting opposite to the direction of the motion of the satellite.
D) The gravitational force acting on the satellite is balanced by the centrifugal force acting on the satellite.

B) There is no component of force acting along the direction of motion of the satellite.

A satellite of mass m has an orbital period T when it is in a circular orbit of radius R around the earth. If the satellite instead had mass 4m, its orbital period would be

A) 4T.
B) T/4.
C) 2T.
D) T.
E) T/2.

D) T.

Two objects attract each other gravitationally. If the distance between their centers decreases by a factor of 2, how does the gravitational force between them change?

A) The gravitational force increases by a factor of 2.
B) The gravitational force decreases by a factor of 4.
C) The gravitational force increases by a factor of 4.
D) The gravitational force remains unchanged.
E) The gravitational force decreases by a factor of 2.

C) The gravitational force increases by a factor of 4.

If the mass of the earth and all objects on it were suddenly doubled, but the size remained the same, the acceleration due to gravity at the surface would become

A) the same as it now is.
B) 1/4 of what it now is.
C) 2 times what it now is.
D) 4 times what it now is.
E) 1/2 of what it now is.

C) 2 times what it now is.

A satellite in a circular orbit of radius R around planet X has an orbital period T. If Planet X had one-fourth as much mass, the orbital period of this satellite in an orbit of the same radius would be

A) T√2
B) T/2.
C) 2T.
D) T/4.
E) 4T.

C) 2T.

The reason an astronaut in an earth satellite feels weightless is that

A) this is a psychological effect associated with rapid motion.
B) the astronaut is beyond the range of the earth's gravity.
C) the astronaut is falling.
D) the astronaut is at a point in space where the effects of the moon's gravity and the earth's gravity cancel.
E) the astronaut's acceleration is zero.

C) the astronaut is falling.

In simple harmonic motion, the speed is greatest at that point in the cycle when

A) the potential energy is a maximum.
B) the kinetic energy is a minimum.
C) the magnitude of the acceleration is a maximum.
D) the displacement is a maximum.
E) the magnitude of the acceleration is a minimum.

E) the magnitude of the acceleration is a minimum.

A frictionless pendulum clock on the surface of the earth has a period of 1.00 s. On a distant planet, the length of the pendulum must be shortened slightly to have a period of 1.00 s. What is true about the acceleration due to gravity on the distant planet?

A) The gravitational acceleration on the planet is equal to g.
B) The gravitational acceleration on the planet is slightly less than g.
C) The gravitational acceleration on the planet is slightly greater than g.
D) We cannot tell because we do not know the mass of the pendulum.

B) The gravitational acceleration on the planet is slightly less than g.

The position x of an object varies with time t. For which of the following equations relating x and t is the motion of the object simple harmonic motion? (There may be more than one correct choice.)
Choose all that apply.

A) x=5sin23t
B) x=5sin3t
C) x=4tan2t
D) x=2cos(3t−1)
E) x=8cos3t

B) x=5sin3t
D) x=2cos(3t−1)
E) x=8cos3t

A mass M is attached to an ideal massless spring. When this system is set in motion with amplitude A, it has a period T. What is the period if the amplitude of the motion is increased to 2A?

A) 2T
B) T/2
C) T4
D) T√2
E) T

E) T

Because the earth's orbit is slightly elliptical, the earth actually gets closer to the sun during part of the year. When the earth is closer to the sun its orbital speed is

A) the same as when the earth is farthest away from the sun.
B) greater than when the earth is farthest away from the sun.
C) less than when the earth is farthest away from the sun.

B) greater than when the earth is farthest away from the sun.

A certain planet has an escape speed V. If another planet of the same size has twice the mass as the first planet, its escape speed will be

A) V.
B) 2V .
C) V/2.
D) √2V .
E) V/√2.

D) √2V .

Earth's orbit around the Sun is slightly elliptical. Thus, Earth actually gets closer to the Sun during part of the year. What happens to Earth's orbital speed when it is closer to the Sun?

A) Earth's orbital speed is the same whether it is closer to the Sun or farther from the Sun.
B) Earth's orbital speed is greater when it is closer to the Sun than when it is farther from the Sun.
C) Earth's orbital speed is less when it is closer to the Sun than when it is farther from the Sun.

B) Earth's orbital speed is greater when it is closer to the Sun than when it is farther from the Sun.

A baseball is located at the surface of the earth. Which statements about it are correct? (There may be more than one correct choice.)

A) The ball exerts a greater gravitational force on the earth than the earth exerts on the ball.
B) The gravitational force on the ball due to the earth is exactly the same as the gravitational force on the earth due to the ball.
C) The earth exerts a much greater gravitational force on the ball than the ball exerts on the earth.
D) The gravitational force on the ball is independent of the mass of the earth.
E) The gravitational force on the ball is independent of the mass of the ball.

B) The gravitational force on the ball due to the earth is exactly the same as the gravitational force on the earth due to the ball.

If the torque on an object adds up to zero...

A) the object could be accelerating linearly but it could not be turning.
B) the forces on it also add up to zero.
C) the object could be both turning and accelerating linearly.
D) the object cannot be turning.
E) the object is at rest.

C) the object could be both turning and accelerating linearly.

The angular momentum of a system remains constant

A) when no net external force acts on the system.
B) when the total kinetic energy is constant.
C) all the time since it is a conserved quantity.
D) when the linear momentum and the energy are constant.
E) when no torque acts on the system.

E) when no torque acts on the system.

A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii and are of uniform density. If the three are released simultaneously at the top of an inclined plane and roll without slipping, which one will reach the bottom first?

A) hollow pipe
B) solid cylinder
C) solid sphere
D) They all reach the bottom at the same time.

C) solid sphere