Conservation of Momentum

Dilbert and his sister, Jolene, are walking around disneyworld during summer vacation. Dilbert throws a wad of chewed bubble gum at his sister. Jolene, because she is very nimble and alert, avoids the gooey projectile and watches it strike a Mickey Mouse balloon that is for sale. The gum sticks to the balloon during the collision and they move together after the collision. If the total momentum of the gum and balloon before the collision was 1 kgm/s the total momentum after the collision would be... A.) 1 kgm/s B.) less than 1 kgm/s C.) more than 1 kgm/s D.) not enough information

A.) 1 kgm/s

Which of the following situations would produce the greatest momentum? A.) a large mass moving at a high velocity B.) a small mass moving at a high velocity C.) a large mass moving at a low velocity D.) a small mass moving at a low velocity

A.) a large mass moving at a high velocity

During what type of collision is kinetic energy conserved? A.) elastic B.) inelastic C.) perfectly inelastic D.) all of these

A.) elastic

True or False. The kinetic energy of an object remains constant during all elastic collisions.

False

Air bags save lives during car crashes because they... A.) apply a large force over a shorter time B.) apply a small force over a longer time C.) apply a large force over a longer time D.) apply a small force over a shorter time

B.) apply a small force over a longer time

Consider the rolling of the object. If the speed of the object doubles, its kinetic energy will be... A.) zero B.) four times larger C.) twice as large D.) unchanged

B.) four times larger

During elastic collisions is momentum or kinetic energy conserved?

Both momentum and kinetic energy are conserved

Suppose you are driving down the highway at 55 mph and a bug crashes into your windshield. Which experiences the greater change in momentum? A.) the bug B.) the car C.) both the same

C.) both the same

If the direction of an objects momentum is east, then the direction of the objects velocity must be... A.) north B.) south C.) east D.) west

C.) east

Two objects, A and B have the same size and shape. However, A has twice the mass of B. Both objects are dropped front a considerable height in a place where no air resistance exists. Object A will have a greater... A.) speed B.) acceleration C.) momentum D.) all of the above

C.) momentum

In a physics lab, an object rolls along a frictionless track with considerable momentum. If the speed of the rolling object doubles, its momentum will be... A.) zero B.) four times larger C.) twice as large D.) unchanged

C.) twice as large

Which of the following situations would produce the smallest impulse on an object? A.) a large force applied over a long time B.) a small force applied over a long time C.) a large force applied over a short time D.) a small force applied over a short time

D.) a small force applied over a short time

Consider a karate expert as she executes a swift kick to a cement block and breaks it with her foot. During the collision between her foot and the block, the... A.) time of impact on both the block and her foot is the same B.) force on both the block and her foot have the same magnitude C.) impulse on both the block and her foot have the same magnitude D.) all of the above

D.) all of the above

During what type of collision is momentum conserved? A.) elastic B.) inelastic C.) perfectly inelastic D.) all of these

D.) all of these

Imagine firing a bullet from a gun. The speed of the bullet leaving the gun will be the same as the speed of the recoiling gun.. A.) because momentum is conserved B.) because velocity is conserved C.) because kinetic energy is conserved D.) only if the mass of the bullet equals the mass of the gun

D.) only if the mass of the bullet equals the mass of the gun

It is not possible for a rocket to accelerate in outer space because... A.) there is no air in space B.) there is no friction on space C.) there is no gravity in space D.) Nonsense, rockets do accelerate in outer space

D.) rockets do accelerate in outer space

In order to catch a baseball, a player naturally moves his hand backward in the direction of the ball's motion upon impact. This reduces the force of impact on the players hand because... A.) the impact velocity is decreased B.) the momentum change is decreased C.) the time of impact is decreased D.) the time of impact is increased

D.) the time of impact is increased

True or False. During a collision, the velocity changes of two objects will always be equal in magnitude.

False

True or False. During a collision, total final velocity equals total initial velocity.

False

True or False. Most collisions tend to be partially or completely elastic.

False, very few are elastic

True or False. If object A has more momentum than object B, object A will have more kinetic energy than object B.

False.

True or False. Any object with mass must have momentum.

False. If it has no velocity the momentum would be zero.

True or False. An object moving east would experience a westward impulse during any collision.

False. Impulse direction depends on the forces direction.

True or False. Impulse is a force.

False. Impulse is a quantity

True or False. Momentum is a form of energy.

False. Momentum is a quantity.

True or False. Momentum is conserved during all collisions, so the momentum of an object never changes.

False. Momentum is conserved in all collisions, but momentum can change.

True or False. If an object is moving to the east and slowing down, its momentum is to the west.

False. Only acceleration is west.

If asked to find the mass of something in a conservation of momentum question what do you do?

Multiply the mass of the object given by that objects (velocity initial - velocity final) and divide it by the (velocity initial - velocity final) of the objects mass you are trying to find.

Is the standard unit for momentum in Newtons?

No, it is measured in kg * m/s

During inelastic collisions is momentum or kinetic energy conserved?

Only momentum

During perfectly inelastic collisions is momentum or kinetic energy conserved?

Only momentum

Two objects have the same momentum. This means that...

Their velocities must be in the same direction, but could have different magnitudes.

True or False. A force of 100 N actin for 0.1 seconds would provide the same impulse as 5 N acting for 2 seconds.

True

True or False. An object that experiences a net impulse will definitely experience a momentum change.

True

True or False. Any mass that is moving at a constant speed must have momentum.

True

True or False. During a collision, an object always encounters an impulse and a momentum change.

True

True or False. If different balls are dropped from rest and collide with the floor, the higher the ball rises, the more elastic its collision with the floor was.

True

True or False. If two different objects are moving at the same speed, the more massive object has more momentum.

True

True or False. If two objects with different masses have the same momentum, the least massive object has more kinetic energy

True

True or False. Impulse is a vector quantity.

True

True or False. Most collisions are not elastic because motion energy is transferred into heat, light, or sound.

True

True or False. Objects involved in collisions experience impulses.

True

True or False. Perfectly elastic and perfectly inelastic collisions are two opposite extremes along a continuum. Most collisions fall somewhere between these extremes, depending on the amount of kinetic energy that is conserved by the objects.

True

True or False. The momentum of an object varies directly with the speed of an object.

True

True or False. The more elastic a collision is, the less kinetic energy will be converted to other forms of energy.

True

True or False. Two colliding objects exert equal forces upon each other even if their masses are different.

True

True or False. When two objects collide, the object with less mass experiences the greater velocity change

True

Is momentum a vector quantity?

Yes