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AP Physics 1: Algebra-Based Practice Quiz: Elastic and Inelastic Collisions

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 10 questions to check your progress.

Question 1 of 10

According to the provided text, which of the following best describes an elastic collision?

All Questions (10)

According to the provided text, which of the following best describes an elastic collision?

A) A collision where the objects stick together.

B) A collision where the total kinetic energy of the system decreases.

C) A collision where the initial kinetic energy of the system is equal to the final kinetic energy.

D) A collision where the objects move with the same velocity after the collision.

Correct Answer: C

The content explicitly states that in an elastic collision, 'the initial kinetic energy of the system is equal to the final kinetic energy of the system.'

What is the defining characteristic of an inelastic collision?

A) The total kinetic energy of the system increases.

B) The total kinetic energy of the system remains constant.

C) The objects involved stick together and move as one.

D) The total kinetic energy of the system decreases.

Correct Answer: D

The provided text defines an inelastic collision as one 'in which the total kinetic energy of the system decreases.' While objects sticking together is a type of inelastic collision, the most general definition is the decrease in kinetic energy.

In a perfectly inelastic collision, what happens to the objects involved after they interact?

A) They bounce off each other with their kinetic energy conserved.

B) They stick together and move with the same velocity.

C) They come to a complete stop, regardless of their initial motion.

D) One object stops while the other moves away with all the initial kinetic energy.

Correct Answer: B

The content specifies that 'In a perfectly inelastic collision, the objects stick together and move with the same velocity after the collision.'

Two balls of soft clay are thrown at each other. They collide and form a single, misshapen lump that continues to move. How would this interaction be classified?

A) Elastic collision

B) Perfectly inelastic collision

C) A collision where kinetic energy is conserved

D) A non-physical interaction

Correct Answer: B

Since the two clay balls 'stick together' and move as a single object after the collision, this is the definition of a perfectly inelastic collision.

A physicist measures the total kinetic energy of a two-cart system before and after they collide. The physicist finds that the final total kinetic energy is less than the initial total kinetic energy. What conclusion can be drawn?

A) The collision was elastic.

B) The collision was inelastic.

C) The carts must have stuck together.

D) An external force must have acted on the system.

Correct Answer: B

The definition of an inelastic collision is one in which the total kinetic energy of the system decreases. While the carts might have stuck together (perfectly inelastic), we only have enough information to conclude that it was, at a minimum, inelastic.

The primary distinction used to describe whether an interaction between objects is elastic or inelastic is based on:

A) The change in the total kinetic energy of the system.

B) Whether or not the objects make physical contact.

C) The masses of the objects involved in the collision.

D) Whether or not the objects stick together after the collision.

Correct Answer: A

The provided content defines both elastic and inelastic collisions based on whether the total kinetic energy of the system is conserved (elastic) or decreases (inelastic). Therefore, the change in kinetic energy is the primary distinction.

If the total kinetic energy of a system is the same both before and after a collision, the collision is described as:

A) Inelastic

B) Perfectly inelastic

C) Elastic

D) Kinetic

Correct Answer: C

This is the direct definition provided in the content: 'An elastic collision between objects is one in which the initial kinetic energy of the system is equal to the final kinetic energy of the system.'

Which of the following statements is ALWAYS true for any inelastic collision?

A) The objects come to a complete stop after the collision.

B) The objects stick together after the collision.

C) The final total kinetic energy of the system is less than the initial total kinetic energy.

D) The final total kinetic energy of the system is zero.

Correct Answer: C

The core definition of an inelastic collision is that kinetic energy decreases. Objects only stick together in a *perfectly* inelastic collision, which is a specific type of inelastic collision. The final kinetic energy is not necessarily zero, and the objects do not necessarily stop.

A student observes a collision and wants to determine if it was perfectly inelastic. Which observation would confirm this?

A) The total kinetic energy of the system decreased by half.

B) The objects bounced off each other at high speeds.

C) The objects were moving with the same velocity after the collision.

D) The total kinetic energy of the system was conserved.

Correct Answer: C

The defining feature of a perfectly inelastic collision is that the objects 'stick together and move with the same velocity after the collision.' Observing them moving with a common velocity is the key confirmation.

An interaction is classified as elastic. What does this imply about the system's kinetic energy?

A) The kinetic energy of each individual object in the system remained constant.

B) The total kinetic energy of the system after the interaction is equal to the total kinetic energy before.

C) The total kinetic energy of the system was converted into other forms of energy.

D) The total kinetic energy of the system decreased, but the objects did not stick together.

Correct Answer: B

The definition of an elastic collision is that the *total* kinetic energy of the *system* is conserved (initial equals final). The kinetic energy of individual objects within the system can change, but the sum remains the same.