Elastic and Inelastic Collisions - AP Physics 1

1. What do we call a collision where objects move together after impact?

   Perfectly inelastic collision. Maximum energy loss occurs when objects stick and move together.

2. What quantity is always conserved in both elastic and inelastic collisions?

   Momentum. Newton's third law ensures momentum conservation in isolated systems.

3. What do we call the loss of kinetic energy in an inelastic collision?

   Energy dissipation. Kinetic energy converts to heat, sound, or deformation.

4. In a collision, if kinetic energy is lost, what type of collision is it?

   Inelastic. Energy converts to heat, sound, or deformation during collision.

5. In an elastic collision, what happens to the relative speed of approach and separation?

   They are equal. Defines elastic collision: approach speed equals separation speed.

6. What is the value of the coefficient of restitution for a perfectly inelastic collision?

   0. No separation occurs; objects move together with zero relative velocity.

7. What happens to total system momentum in any type of collision?

   It remains constant. Newton's third law ensures momentum conservation in all collisions.

8. During a collision, if the total kinetic energy increases, what might be occurring?

   External work performed on the system. Additional energy input from explosion or spring release mechanism.

9. What is the formula for the coefficient of restitution?

   $e = \frac{v_2' - v_1'}{v_1 - v_2}$. Relates relative velocities before and after collision impact.

10. In a collision, if the objects do not stick and kinetic energy is conserved, what type is it?

    Elastic collision. Objects separate after collision with kinetic energy preserved.

11. What is the definition of an elastic collision?

    A collision where total kinetic energy is conserved. Both momentum and kinetic energy are preserved throughout the collision.

12. In which type of collision might sound, heat, or deformation occur?

    Inelastic collision. Energy converts to heat, sound, and permanent deformation.

13. In a perfectly inelastic collision, what happens to the colliding objects?

    They stick together post-collision. Objects combine into a single mass moving with common velocity.

14. Identify the primary characteristic of a perfectly elastic collision.

    Total kinetic energy is conserved. No kinetic energy is lost to other forms like heat or sound.

15. In a collision where two cars stick together, what type of collision is it?

    Perfectly inelastic collision. Objects join together, maximizing kinetic energy loss in collision.

16. Name a real-world example of an inelastic collision.

    A car crash. Deformation and energy loss characterize real-world inelastic impacts.

17. What is the result when two objects collide elastically and their masses are equal?

    They swap velocities. Equal masses in elastic collision exchange velocities completely.

18. What is the key difference between elastic and inelastic collisions regarding energy?

    Elastic conserves kinetic energy; inelastic does not. Elasticity is defined by whether kinetic energy is preserved.

19. For an inelastic collision, is the coefficient of restitution less than, equal to, or greater than 1?

    Less than 1. Energy loss reduces the relative separation speed after collision.

20. State the formula for conservation of momentum in a collision.

    $m_1v_1 + m_2v_2 = m_1v_1' + m_2v_2'$. Total momentum before equals total momentum after collision.

21. State the equation for kinetic energy conservation in elastic collisions.

    $\frac{1}{2}m_1v_1^2 + \frac{1}{2}m_2v_2^2 = \frac{1}{2}m_1v_1'^2 + \frac{1}{2}m_2v_2'^2$. Total kinetic energy before collision equals total after collision.

22. What is the key principle that distinguishes collision types?

    Conservation of kinetic energy. Kinetic energy conservation determines elastic versus inelastic classification.

23. What happens to the kinetic energy in a perfectly inelastic collision?

    It is not conserved. Maximum energy loss occurs when objects stick together.

24. Name a real-world example of an elastic collision.

    Colliding billiard balls. Hard spheres approximate elastic behavior in ideal conditions.

25. What is the definition of an inelastic collision?

    A collision where total kinetic energy is not conserved. Momentum is conserved, but some kinetic energy converts to other forms.

26. In a perfectly elastic collision, how does the kinetic energy before compare to after?

    It is the same. Perfect elasticity means no energy is lost during collision.

Study these flashcards