Middle School Science Quiz: Motion And Energy Transfer

What this quiz covers

This quiz focuses on Motion And Energy Transfer, giving you a quick way to practice the rules, question types, and explanations that matter most for Middle School Science.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. $8\,\text{J}$
2. $16\,\text{J}$ (correct answer)
3. $32\,\text{J}$
4. $0\,\text{J}$

Question 2

1. The cue ball loses kinetic energy and the target ball gains kinetic energy; some energy may also be converted to sound/heat. (correct answer)
2. The cue ball gains kinetic energy because it is still moving after the collision.
3. The target ball loses kinetic energy because it was hit.
4. No energy transfer occurs because both balls move forward.

Question 3

1. Mostly energy transfer: the cue ball's kinetic energy moves to the other ball as kinetic energy. (correct answer)
2. Mostly energy conversion: the cue ball's kinetic energy turns completely into potential energy.
3. No transfer occurs because both balls have the same mass.
4. Energy is destroyed because the cue ball stops moving.

Question 4

1. About 18 J of kinetic energy is transferred from the bob to the block, and about 2 J is converted to sound/heat; total energy is conserved. (correct answer)
2. The block created 18 J of kinetic energy because it started from rest.
3. The bob's kinetic energy disappears because it stops, so energy is not conserved.
4. All 20 J must transfer to the block as kinetic energy, so the block must have 20 J after.

Question 5

1. The cue ball gains kinetic energy; the target ball loses kinetic energy.
2. Both balls gain kinetic energy because they are both involved in the collision.
3. The cue ball loses kinetic energy; the target ball gains kinetic energy. (correct answer)
4. Neither ball changes kinetic energy because momentum is conserved.

Question 6

1. The moving cart changes color during the collision.
2. One cart slows/stops while the other starts moving faster, showing one lost kinetic energy while the other gained it. (correct answer)
3. The carts are the same mass, so energy must always be created.
4. The carts touch, so energy automatically disappears.

Question 7

1. 0 J
2. 10 J (correct answer)
3. 60 J
4. 70 J

Question 8

1. 0 J
2. 8 J
3. 16 J (correct answer)
4. 32 J

Question 9

1. Cart A changes color during the collision.
2. Cart A slows down to a stop while cart B starts moving and speeds up. (correct answer)
3. The carts touch for a short time, so energy must be created.
4. Cart B was at rest, so it cannot gain kinetic energy.

Question 10

1. It is greater after the collision because both carts are moving.
2. It is the same: $16\,\text{J}$ before and $10\,\text{J}$ after.
3. It is smaller after the collision: $16\,\text{J}$ before and $10\,\text{J}$ after, so some energy was converted to sound/thermal energy. (correct answer)
4. It is smaller after the collision because kinetic energy is always destroyed in collisions.

Question 11

1. Energy is not conserved because the total kinetic energy decreased from 20 J to 18 J.
2. About 2 J of energy was transferred from the block back to the bob.
3. About 18 J transferred from the bob to the block, and about 2 J was converted to sound/thermal energy. (correct answer)
4. The block gained 20 J, but it is not shown because kinetic energy cannot be measured.

Question 12

1. Before: $6\,\text{J}$; After: $6\,\text{J}$ (correct answer)
2. Before: $12\,\text{J}$; After: $6\,\text{J}$
3. Before: $6\,\text{J}$; After: $12\,\text{J}$
4. Before: $0\,\text{J}$; After: $6\,\text{J}$

Question 13

1. All 16 J of kinetic energy stayed as kinetic energy because the carts stuck together.
2. Kinetic energy increased because sticking together creates energy.
3. Some kinetic energy transferred to cart B, but some was converted to sound/thermal energy because the collision was inelastic. (correct answer)
4. No energy transfer occurred because cart B was not moving before the collision.

Question 14

1. Cart B transfers kinetic energy to cart A because cart A is still moving after the collision.
2. Cart A transfers kinetic energy to cart B because A's speed decreases while B starts moving. (correct answer)
3. No kinetic energy is transferred because both carts move in the same direction.
4. Both carts gain kinetic energy because they are moving after the collision.

Question 15

1. 0 J (no energy is transferred because cart A stops)
2. 8 J
3. 16 J (correct answer)
4. 32 J

Question 16

1. The pins transfer kinetic energy to the ball, causing the ball to slow down.
2. The ball transfers about 70 J of kinetic energy away; about 60 J becomes the pins' kinetic energy and about 10 J becomes sound/heat, so total energy is conserved. (correct answer)
3. Kinetic energy is destroyed because the total kinetic energy after is less than before, so energy is not conserved.
4. The ball's lost kinetic energy must all become the pins' kinetic energy, so there is no sound or heat.

Question 17

1. Total kinetic energy is larger after; energy was created during the collision.
2. Total kinetic energy is smaller after; the "missing" energy was destroyed.
3. Total kinetic energy is smaller after; some kinetic energy was converted to sound/heat even though total energy is conserved. (correct answer)
4. Total kinetic energy is the same; therefore no energy was transferred between carts.

Question 18

1. The moving cart transfers some of its kinetic energy to the stationary cart, and some kinetic energy is converted to other forms because total KE decreases. (correct answer)
2. The stationary cart transfers kinetic energy to the moving cart because it starts moving.
3. No energy transfer occurs because both carts are moving after the collision.
4. Total kinetic energy must increase in any collision because two objects are moving afterward.

Question 19

1. The first cart's speed decreases while the second cart's speed increases from $0$ to a nonzero value. (correct answer)
2. Both carts are made of the same material.
3. The carts touch for a very short time.
4. The carts have different colors, so energy moves from the darker cart to the lighter cart.

Question 20

1. Cart A loses $16\,\text{J}$ of KE and Cart B gains $8\,\text{J}$; the missing $8\,\text{J}$ means energy was destroyed.
2. Cart A gains KE because it is still moving after the collision.
3. Cart A loses $16\,\text{J}$ of KE and Cart B gains $8\,\text{J}$; about $8\,\text{J}$ is converted to thermal/sound energy. (correct answer)
4. No KE is transferred because both carts move after the collision.