Physics Exam 1

What path would an object tossed at an angle with gravity most likely follow?

a curved path

A ball is tossed horizontally with the speed of 5 m/s.  What is its speed after 2 seconds ?

20.62 m/s

Nellie tosses a ball upward at an angle. Assuming no air resistance, which component of velocity changes with time?

the vertical component.

A ball rolls off the edge of a table at the same time another ball drops vertically from the same table. The ball to hit the floor first is the

both hit at the same time.

A ball is thrown upward and caught when it returns. Compared with its initial speed and in the presence of air resistance, the speed with which it is caught is

less

While a rock thrown upward at 50 degrees to the horizontal rises, neglecting air drag, its vertical component of velocity

decreases

While a rock thrown upward at 50 degrees to the horizontal rises, neglecting air drag, its horizontal component of velocity

remains unchanged.

What is the angle a projectile being thrown to achieve the maximum range when air resistance is negligible ?

45 degrees

A hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?

the one dropped.

A hunter on level ground fires a bullet at an angle of 10 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?

the one fired.

A bullet fired horizontally over level ground hits the ground in 0.5 second. If it had been fired with twice the speed it would have hit the ground in

0.5s

A projectile is launched from ground level at 15° above the horizontal and lands downrange. What other projection angle for the same speed would produce the same down-range distance?

75°

A ball is tossed upward. Neglecting air drag, the acceleration along its path is

g downward

An object is dropped and freely falls to the ground with acceleration g. If it is thrown upward at an angle instead, neglecting air drag, the acceleration along its path will be

the same

A projectile is launched vertically upward at 50 m/s. If air resistance does affect motion, then its speed upon returning to its starting point is

less than 50 m/s

If you throw a stone horizontally from the top of a cliff, one second after leaving your hand its vertical distance below the top of the cliff is

5m

An Earth satellite is simply a projectile

freely falling around the Earth

The circular path of a satellite orbiting Earth is characterized by a constant

speed, acceleration, radial distance

Minimal orbit speed about Earth is about 

8 km/s

A projectile that is fired vertically from the surface of Earth at 5 km/s will

rise and fall back to Earth's surface (because it never got above 8 km/s, it cannot break out of the Earth’s atmosphere into space, so it will fall back down)

When comparing two cannonballs shot out of separate cannons, one longer, one shorter. The canon ball in the longer barrel has more

time of the push of the gas, impulse, change of momentum, velocity coming out of the cannon

When comparing two cannonballs shot out of separate cannons, one longer, one shorter. The canon ball in the longer barrel has the same _______ as the shorter one

force applied

A truck is moving with a velocity of 50 mi/hr. it loses control of its brake and has to stop. The truck is given two choices to stop: hitting a brick wall or a haystack.

The change of momentum experience by the truck if it hits the brick wall if (more than / the same as / less than) the change of momentum experienced by the truck if it hits the haystack.

the same as

A truck is moving with a velocity of 50 mi/hr. it loses control of its brake and has to stop. The truck is given two choices to stop: hitting a brick wall or a haystack.

The impulse experience by the truck if it hits the brick wall if (more than / the same as / less than) the impulse experienced by the truck if it hits the haystack.

the same as

A truck is moving with a velocity of 50 mi/hr. it loses control of its brake and has to stop. The truck is given two choices to stop: hitting a brick wall or a haystack.

The force experience by the truck if it hits the brick wall if (more than / the same as / less than) the force experienced by the truck if it hits the haystack.

more than

what is the momentum of an 8kg bowling ball rolling at 2 m/s

16 kg x m/s

what impulse occurs when the average force of 10 N is exerted on a cart for 2.5 s

25 N x S

How much impulse stops a 50 kg carton sliding at 4 m/s when it meets a rough surface?

200 kg x m/s

What is the formula for momentum

m = mass x velocity

what is the formula for impulse?

impulse = force x time

A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the opposite direction has a speed of

0 m/s

The speedometer of an automobile reads

instantaneous speed

The two measurements necessary for calculating average speed are

distance and time

When you walk at an average speed of 4 m/s, in 5 s you'll cover a distance of

20 m

A vehicle undergoes acceleration when it

gains or loses speed OR changes direction

The average speed of a horse that gallops 10 kilometers in 30 minutes is

20 km/h

While a car travels around a circular track at a constant speed, its

velocity IS NOT zero, nor is its acceleration

If an object moves with constant acceleration, its velocity must

change by the same amount each second

A cart maintains a constant velocity of 100 m/s for 10 seconds. During this interval its acceleration is

zero

A cart changes its speed from 90 m/s to 100 m/s in 10 seconds. During this interval its acceleration is

1 m/s²

A car's speed 3 seconds after accelerating from rest at 2 m/s² is

6 m/s

If a car increases its velocity from zero to 60 m/s in 10 seconds, its acceleration is

6 m/s²

A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

directed downward

When a ball thrown straight upwards reaches the very top of its path, its acceleration is

10 m/s²

A freely-falling watermelon falls with constant

acceleration

While an iron block near the Earth's surface is in free fall, it undergoes an increase in

speed

Twelve seconds after starting from rest, a freely-falling cantelope has a speed of

more than 100 m/s

If a stone falls to the bottom of a mineshaft in 6 seconds, then the depth of the shaft is about

180m

If a freely falling object were equipped with a speedometer, its speed reading would increase each second by about

10m/s

An apple falls from a tree and hits the ground 5 meters below with a speed of about

10 m/s

A tree stump is pulled northward by a 10 N force at the same time a 25 N force pulls it southward. The resultant force has a magnitude and direction of

15 N southward

The force of friction on a sliding object is 10 N. The applied forced needed to maintain a constant velocity is

10 N

The support force on a 10N book at rest on a table is ______ N

10

A gymnast with the weight 650 N is hanging still suspended by a vertical rope. The tension by the rope is ______ N

650

Which statements are correct to describe an object at a state of equilibrium?

1. object at rest

2. object is moving in a steady straight path

3. object is with constant acceleration

4. net force on it is zero

1,2,4

the force that is supporting an object against the gravity pull is called

support force

if no external forces act on a moving object, it will

continue moving at the same speed

the first scientist to introduce the concept of inertia was

Galileo

consider a ball resting in the middle of a cart. When you quickly jerk the cart forward, the ball

hits the back of the cart

Which of the following is not a vector quality

1. speed

2. velocity

3. force

4. all are vector quantities

1. speed

According to Galileo, inertia is a

property of all matter

The amount of force needed to sustain motion of a rock in outer space is

1. a force equal to its weight

2. a force less than its weight if friction is absent

3. none of these

3. none of these

An object is pulled with three forces: one at 20 N to the right, another at 40 N to the right, and the third at 30 N to the left. The net force is

1. 60 N to the left

2. 30 n to the left

3. 60 N to the right

4. none of the above

4. none of the above

A 50-N object falling in air experiences 30 N of air resistance. The amount of net force on the falling object is

20 N

Whenever the net force on an object is zero, its acceleration

is zero

When a 10-N object is suspended at rest by two vertical strands of rope, the tension in each rope is

5N

You hang from a pair of gym rings and the upward support forces of the rings will always

add up to equal your weight

Nellie hangs from a pair of ropes at an angle. Tension in the ropes depends on the

angle of the ropes

Place a book that weighs 10 N on a horizontal surface and the support force on the book is

10 N

When you stand at rest on a pair of bathroom scales, the readings on the scales will always

add up to equal your weight

A bucket of cement is raised by a rope at constant speed at a construction site.  The upward force on the bucket supplied by the rope is

equal to force of gravity

The equilibrium rule ΣF = 0 applies to

objects / systems in uniform motion in a straight line AND objects / systems at rest

When a crate slides down an incline at a constant velocity it is

in dynamic equilibrium

A 10-N falling object encounters 4 N of air resistance. The net force on the object is

6N

The mass of a pet turtle that weighs 10 N is about

1 kg

A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is

3000 N

A push on a 1-kg brick accelerates it. Neglecting friction, equally accelerating a 10-kg brick requires

10 times as much force

A car has a mass of 1000 kg and accelerates at 2 m/s². What net force is exerted on the car?

2000 N

A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s2. What is the mass of the car?

1500 kg

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction. The particle with both forces acting

continues at the speed it had when it encountered the second force.

A 10-kg brick and a 1-kg apple are dropped in a vacuum. The force of gravity on the brick is

10 times more than the force on the apple

A single brick falls with acceleration g. The reason a double brick falls with the same acceleration is

its ratio of force to mass is the same.

When a falling object has reached its terminal velocity, its acceleration is

zero

Suzie Skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration

decreases

A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to a state of zero acceleration first?

the light woman

When a boxer hits a punching bag, the strength of his punch depends on how much force the bag can

exert on the boxer’s fist

A piece of rope is pulled by two people in a tug-of-war. Each exerts a 400-N force. What is the tension in the rope?

400 N

The force exerted on the tires of a car that directly accelerate it along a road is exerted by the

road