Lesson 6.2.1

6.2.1 Elastic and inelastic collisions and kinetic energy Quiz: Pearson Edexcel Physics, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 6.2.1, Elastic and inelastic collisions and kinetic energy: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 6: Further Mechanics, written with Revision Ninja.

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The 20 questions

  1. What defines an elastic collision?

    • The total mass of the colliding objects increases by the mass of the impact energy
    • The total kinetic energy of the colliding objects is conserved
    • The total kinetic energy of the colliding objects is always reduced to zero
    • The objects always move together in the same direction after colliding

  2. What happens to kinetic energy in an inelastic collision?

    • Kinetic energy is created so the total energy after the collision is greater than before
    • Kinetic energy is unchanged because only momentum is transferred during the impact
    • Some kinetic energy is transferred to other forms such as thermal energy, sound or deformation
    • All kinetic energy is converted into gravitational potential energy during the impact

  3. Kinetic energy of a non-relativistic particle can be written in terms of its momentum p and mass m as which expression?

    • E_k = p^2 / (2m)
    • E_k = p / (2m)
    • E_k = p^2 / m
    • E_k = 2m / p^2

  4. A perfectly inelastic collision is one in which which of the following happens?

    • The colliding objects stick together and move with a common velocity afterwards
    • The colliding objects rebound from each other with equal and opposite velocities
    • The colliding objects pass through each other with no change in their speed
    • The colliding objects separate with the same total kinetic energy as before

  5. An object of mass 0.20 kg has kinetic energy 4.0 J. What is its momentum?

    • 0.80 kg m s^-1
    • 2.0 kg m s^-1
    • 1.3 kg m s^-1
    • 4.0 kg m s^-1

  6. Two 0.50 kg trolleys move towards each other at 2.0 m s^-1 and stick together after a head-on collision. How much kinetic energy is lost?

    • 1.0 J
    • 4.0 J
    • 0 J
    • 2.0 J

  7. A 1.0 kg trolley moving at 4.0 m s^-1 hits an identical trolley at rest in an elastic head-on collision. What is the velocity of the second trolley afterwards?

    • 8.0 m s^-1
    • 4.0 m s^-1
    • 0 m s^-1
    • 2.0 m s^-1

  8. A 2.0 kg trolley moving at 3.0 m s^-1 collides with a 1.0 kg trolley at rest and they stick together. How much kinetic energy is lost?

    • 9.0 J
    • 1.5 J
    • 6.0 J
    • 3.0 J

  9. In the previous collision, what percentage of the initial kinetic energy is lost?

    • 50 per cent
    • 25 per cent
    • 33 per cent
    • 67 per cent

  10. A 0.60 kg ball moving at 5.0 m s^-1 rebounds from a smooth wall at 5.0 m s^-1 in the opposite direction, with no energy lost. What is its change in kinetic energy?

    • 15 J
    • 0 J
    • 7.5 J
    • -7.5 J

  11. Two objects have equal momentum magnitudes of 8.0 kg m s^-1. One has mass 2.0 kg and the other has mass 4.0 kg. What is the ratio of kinetic energy of the 2.0 kg object to that of the 4.0 kg object?

    • 1:2
    • 2:1
    • 4:1
    • 1:4

  12. A 1.5 kg object has momentum 6.0 kg m s^-1. What is its kinetic energy?

    • 9.0 J
    • 6.0 J
    • 12 J
    • 24 J

  13. A 0.25 kg ball moving at 4.0 m s^-1 hits a 0.75 kg ball at rest in an elastic head-on collision. What is the velocity of the 0.75 kg ball afterwards?

    • 4.0 m s^-1 in the original direction of motion
    • 2.0 m s^-1 in the original direction of motion
    • 3.0 m s^-1 in the original direction of motion
    • 1.0 m s^-1 in the original direction of motion

  14. In the collision of a 0.25 kg ball at 4.0 m s^-1 with a stationary 0.75 kg ball, what fraction of the initial kinetic energy is transferred to the 0.75 kg ball?

    • 50 per cent
    • 25 per cent
    • 100 per cent
    • 75 per cent

  15. A 0.40 kg trolley moving at 6.0 m s^-1 sticks to a stationary 0.20 kg trolley. How much kinetic energy is lost?

    • 2.4 J
    • 1.2 J
    • 7.2 J
    • 4.8 J

  16. A student says a collision must be elastic because momentum is conserved. Which response is correct?

    • The student is wrong, because momentum is conserved in every collision, so kinetic energy must be checked to classify it
    • The student is wrong, because momentum is never conserved in any collision between two objects
    • The student is right, because a collision that conserves momentum always conserves kinetic energy
    • The student is right, because momentum is conserved only in elastic collisions

  17. Why is kinetic energy lost in an inelastic collision?

    • Some of it is cancelled by an equal amount of kinetic energy in the opposite direction
    • Some of it is converted into a larger momentum of the combined objects after the impact
    • Some of it is stored as gravitational potential energy as the objects rise slightly
    • Some of it is converted to internal energy such as thermal energy, sound and permanent deformation

  18. A 2.0 kg object moves at 5.0 m s^-1 and collides with a 3.0 kg object at rest. They stick together. What is the kinetic energy of the combined object afterwards?

    • 25 J
    • 5 J
    • 10 J
    • 15 J

  19. An object has kinetic energy 8.0 J and momentum 4.0 kg m s^-1. What is its mass?

    • 0.50 kg
    • 2.0 kg
    • 1.0 kg
    • 4.0 kg

  20. Two identical 1.0 kg trolleys move towards each other at 3.0 m s^-1 and stick together. How much kinetic energy is lost?

    • 4.5 J
    • 18 J
    • 9.0 J
    • 0 J

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