AP Physics Momentum Concepts

A 1-N apple falls to the ground. The apple hits the ground with an impact force of

1 Newton

When you jump off a step, you usually bend your knees as you reach the ground. By doing this, the time of the impact is about 10 times more than what it would be in a stiff-legged landing, and the average force on your body is reduced by

10 times

A piece of putty moving with 2 units of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, both are set in motion with a combined momentum that is

2 units of momentum

A ball is moving at 6 m/s and has a momentum of 24 kgm/s. What is the ball's mass?

4-kg

A 4-kg ball has a momentum of 20 kgm/s What is the balls speed?

5 m/s

A 5 kg chunk of putty moving at 10m/s collides with and sticks to a 7kg bowling ball that is initially at rest. The bowling ball with its putty passenger will then be set in motion with a momentum of

50 kgm/s

A 2-kg ball is thrown at 3m/s. What is the ball's momentum?

6 kgm/s

A freight train rolls along a track with considerable momentum. If it were to roll at the same speed but had twice as much mass, its momentum would be

Doubled

Suppose an astronaut in outer space wishes to toss a ball against a very massive and perfectly elastic concrete wall and catch it as it bounces back. If the ball is as massive as the astronaut, then

He will never be able to catch it

A cannonball shot from a long-barrel cannon travels faster than one shot from a short-barrel cannon because the cannonball receives a greater

Impulse

The momentum change of an object is equal to the

Impulse- Ft=m(change in v)

In order to increase the final momentum of a golf ball, we could

Increase force acting on it, follow through when hitting (increase time) Increase time of contact, swing as hard as possible

The force of an apple hitting the ground depends on

Its speed before hitting Time of impact If it bounces or not Air resistance on the apple

Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?

Large truck- has more mass

A car traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has

Less distance to stop More mass More momentum

A small economy car and a limousine are pushed from rest across a parking lot, equal distances with equal froces. The car that receives the greater impulse is the

Limo- equal force requires more time so greater impulse

Which of the following has the largest momentum?

Pickup truck traveling down the highway

A piece of putty and a rubber ball have the same mass. If you drop them from the same height which one will produce a greater impulse and why?

Rubber ball will bounce- so greater change in speed means increased momentum

Superman is at rest in space when he throws an asteroid that has more mass than he does. Which moves faster, Superman or the asteroid?

Superman

The force that accelerates a rocket into outer space is exerted on teh rocket by

The exhaust gases

In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because

The time of impact is increased so force is decreased.

Suppose a girl is standing on a pond where there is no friction between her feet and the ice. In order to get off the ice she can

Throw a heavy object- ball goes in one direction and she goes in the other.

A cannon recoils from launching a cannonball. The speed of the cannon's recoil is small because the

cannon has much more mass

If all people, animals, trains and trucks all over the world began to walk or run towards teh east, then

earth would spin a bit slower

A karate expert executes a swift blow and splits a cement block with her bare hand

force of hand and block are the same, time of impact is same, impulses are same magnitude

A moving freight car runs into an identical car at rest on the track. The cars couple together. Compared to the velocity of the first car before the collision the velocity of the combined cars is

half

A cannon fires a cannonball. The speed of the cannonball will be the same as the speed of the recoiling cannon

if the masses are the same

The reason padded dashbords are used in cars is that they

increase the time of collisions so decrease the force

Suppose a cannon is made of a strong but very light material. Suppose that also the cannonball is more massive than the cannon itself. For such a system

its safer to stand in front of the cannon

The momentum of an object is defined as

its velocity times its mass

Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, the reach the ground at the same time, but A has a higher

momentum

Compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles per hour has

more momentum

A table tennis ball moving wiht 5 units of momentum strikes and bounces backward off a heavy bowling all that is initially at rest and free to move. The bowling ball is set in motion with a momentum of

more than 5 units

Momentum of a system is only conserved when there is no

net external force

A collision is considered elastic if

no lasting deformation, momentum conserved, bounce off of eachother

A table tennis ball launcher is fired. Compared to the impulse on the ball, the impulse on the launcher is

the same

A table tennis ball launcher is fired. compared to the force on the ball, the force on the launcher is

the same (Newton's third law)

While roller skating, Granny collides iwht her tiny grandson Ambrose who is at rest. Ignoring any friction effects, Ambroses speed after the collision will be greatest when

they bounce off of eachother

If the momentum of an object changes and its mass remains constant,

velocity changes (accelerating or decelerating), Force acts upon it

Recoil is noticeable if you throw a heavy ball while standing on roller skates. If instead you go through the motions of throwing the ball but hold onto it, your net recoil velocity will be

zero

Two gliders having the same mass and speed move toward eachother on an air track and stick together. After the collision, the velocity of the gliders is

zero