Physics Chapter 3: Projectile Motion & Vectors

4

For a cannon on Earth, the cannonball would follow path 2. Instead, if the same cannon were on the Moon, where g = 1.6 m/s2, which path would the cannonball take in the same situation?

R = B + A

Express the vector R in terms of A, B, C, and D, the edges of a parallelogram

vQ < vP = vR

A ball is thrown as shown in a parabolic path. Assume no air resistance. Point Q is at the highest point of the path and points P and R are at the same height. How do the speeds of the ball at the three points compare?

The spring-loaded gun can launch projectiles at different angles with the same launch speed. At what angle should the projectile be launched in order to travel the greatest distance before landing?

45°

A river flowing west to east at speed 3 m/min. A man on the south bank of the river , capable of swimming at 6m/min in still water , wants to swim across the river in shortest time. He should swim in a direction:

Due north

A small cart is rolling at constant velocity on a flat track. It fires a ball straight up into the air as it moves. After it is fired, what happens to the ball?

it falls right back into the cart

A bullet is fired at an angle of 45°. Neglecting air resistance, what is the direction of acceleration during the flight of the bullet?

downward

If vector u (3,1) and vector v (-1,2) are added, what is the x component of the resultant?

2

A golfer drives her golf ball from the tee down the fairway in a high arcing shot. When the ball is at the highest point of its flight:

the x-velocity is non-zero and the y-velocity is zero

A cart is being pulled along a horizontal track by an external force (a weight hanging over the table edge) and accelerating. It fires a ball straight up out of the cannon as it moves. After it is fired, what happens to the ball?

it falls behind the cart

50 cos 32°

Consider the following velocity vector, V0, Which expression would allow you to solve for the for the original horizontal velocity vector, V0X?

You are trying to hit a friend with a water balloon. He is sitting in the window of his dorm room directly across the street. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him? (Assume that the shot does have enough speed to reach the dorm across the street. )

yes, it hits

A small cart is now rolling down an inclined track and accelerating. It fires a ball straight up out of the cannon as it moves. After it is fired, what happens to the ball?

it falls right back into the cart

A rocket is fired at 30°. If the initial horizontal velocity (vix) is 326 m/s, what is the initial vertical velocity (viy)?

188 m/s

For a projectile, what is the acceleration in the x-direction?

0 m/s^2

down

A stone is thrown horizontally and follows the path XYZ as shown. The direction of the acceleration of the stone at point Y is:

When two vectors A and B of magnitudes "a" and "b" are added ; the magnitude of resultant vector is:

Not greater than (a+b)

A certain vector has x and y components that are equal in magnitude. Which of the following is a possible angle for this vector, in a standard x-y coordinate system?

45°

All have the same hang time

Which of the 3 punts has the longest hang time

From the same height (and at the same time), one ball is dropped and another ball is fired horizontally. Which ball has the greater velocity at ground level?

the "fired" ball

down

A ball is thrown as shown in a parabolic path. Assume no air resistance. Point Q is at the highest point of the path and points P and R are at the same height. Which of the following diagrams best shows the direction of the acceleration of the ball at point P ?

If two vectors are given such that A + B = 0, what can you say about the magnitude and direction of vectors A and B?

same magnitude, must be in opposite directions

For a projectile launched with an initial velocity of 100 m/s, which of the following launch angles, (with respect to the horizontal) will produce the trajectory with the longest horizontal range?

45°

Given that A + B = C, and that lAl^2 + lBl^2 = lCl^2, how are vectors A and B oriented with respect to each other?

they are perpendicular to each other

From the same height (and at the same time), one ball is dropped and another ball is fired horizontally. Which one will hit the ground first?

they both hit at the same time

If each component of a vector is doubled, what happens to the angle of that vector?

it does not change

Given that A + B = C, and that lAl + lBl = lCl, how are vectors A and B oriented with respect to each other?

they are parallel and in the same direction

A soccer ball is kicked at a 55° angle with an initial velocity of 8 m/s. What is the vertical (vyf) velocity of the ball as it hits the ground?

-6.6 m/s

For a projectile launched with an initial velocity of 100 m/s, which of the following launch angles, (with respect to the horizontal) will produce the trajectory with the least time in the air?

10°

2

A battleship simultaneously fires two shells at two enemy submarines. The shells are launched with the same initial velocity. If the shells follow the trajectories shown, which submarine gets hit first?

d + e = f

Six vectors, a through f have the magnitudes and directions indicated in the figure. Which of the following statements is true?

Z

A bowling ball accidentally falls out of the cargo bay of an airliner as it flies along in a horizontal direction. As observed by a person standing on the ground and viewing the plane as in the figure, which path would the bowling ball most closely follow after leaving the airplane?

You drop a package from a plane flying at constant speed in a straight line. Without air resistance, the package will:

remain vertically under the plane while falling

A projectile is launched from the ground at an angle of 30. At what point in its trajectory does this projectile have the least speed?

at the highest point in its flight