Question

d. when energy is destroyed

1. which quantities are conserved in an elastic collision?

a. momentum only
b. kinetic energy only
c. momentum and kinetic energy
d. force and acceleration

1. what happens to kinetic energy in an inelastic collision?

a. it increases
b. it is conserved
c. it is destroyed
d. it changes into other forms of energy

1. which situation best represents an elastic collision?

a. two cars crashing and sticking together
b. a football tackle
c. a cue ball striking another pool ball
d. a car hitting a wall

1. which statement is true for both elastic and inelastic collisions?

a. kinetic energy is conserved
b. momentum is conserved in a closed system
c. objects always stick together
d. energy is lost from the system

part b: short answer

1. describe one difference between elastic and inelastic collisions.

elastic collisions conserve kinetic energy; inelastic ones do not

1. give one real-life example of an inelastic collision and explain why it is inelastic.

a glass shattering on the floor. kinetic energy is used to break the glass, so kinetic energy is not conserved.

part c: data thinking (conceptual)
two carts collide on a frictionless track. after the collision, the total momentum of the system remains the same, but the carts do not bounce apart.

1. is this collision elastic or inelastic? circle one: elastic / inelastic

what evidence support your answer?
extension (optional )
why is momentum conserved in both elastic and inelastic collisions but kinetic energy is not

Explanation:

Multiple Choice Questions (2-5)

Step1: Recall elastic collision rules

Elastic collisions conserve both momentum and kinetic energy. So for question 2, the correct option is C.

Step2: Recall inelastic collision KE behavior

In inelastic collisions, kinetic energy is not conserved; it converts to other forms. So for question 3, the correct option is D.

Step3: Identify real elastic collision example

A cue ball striking a pool ball (negligible kinetic energy loss to heat/sound) is elastic. So for question 4, the correct option is C.

Step4: Recall collision conservation laws

In closed systems, momentum is conserved for both collision types. So for question 5, the correct option is B.

1. The core difference lies in kinetic energy conservation: elastic collisions retain total kinetic energy, while inelastic collisions do not.
2. The example is valid: when a glass shatters on the floor, kinetic energy from the fall is used to break the glass (converted to sound, deformation, and thermal energy), so kinetic energy is not conserved, making it inelastic.

1. The collision is inelastic because the carts do not bounce apart, indicating kinetic energy is lost (e.g., to deformation, sound). For the extension: Momentum conservation comes from Newton's third law (equal and opposite forces act for the same time, so total momentum change is zero) and applies to closed systems regardless of energy transfer. Kinetic energy is not conserved in inelastic collisions because it is converted to other forms of energy, while elastic collisions have no net conversion of kinetic energy to other forms.

Answer:

1. C. Momentum and kinetic energy
2. D. It changes into other forms of energy
3. C. A cue ball striking another pool ball
4. B. Momentum is conserved in a closed system

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Short Answer Questions (6-7)