Lesson 3.3.1

3.3.1 Work and conservation of energy Quiz: OCR Physics, Unit 2

20 questions

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Lesson 3.3.1, Work and conservation of energy: 20 multiple choice questions for the OCR Physics (H156), Unit 2: Forces and motion, written with Revision Ninja.

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The 20 questions

  1. The S.I. unit of work done is the joule, which is equal to:

    • N s
    • N m
    • kg m s^-1
    • N m^-1
  2. What happens to total energy in a closed, isolated system?

    • It gradually decreases
    • It remains constant
    • It drops to zero
    • It continuously increases
  3. The work done by a constant force F that moves its point of application through distance x at angle θ to the force is:

    • W = F x tan θ
    • W = F / cos θ
    • W = F x sin θ
    • W = F x cos θ
  4. How much work is done by a force acting perpendicular to motion?

    • Maximum work
    • Force times distance
    • Zero
    • Negative work
  5. What quantity is equal to the mechanical energy transferred by a force?

    • Work done
    • Force applied
    • Momentum change
    • Power output
  6. Into which main energy store is work done against friction dissipated?

    • Gravitational potential store
    • Thermal energy store
    • Chemical energy store
    • Elastic potential store
  7. Efficiency is the ratio of useful energy output to what quantity?

    • Work against friction
    • Wasted energy output
    • Total power loss
    • Total energy input
  8. A 10 N force acts along a 4 m displacement at 60° to the displacement. What work is done?

    • 35 J
    • 20 J
    • 40 J
    • 10 J
  9. A 4 kg object moves at 5 m s^-1. What is its kinetic energy?

    • 10 J
    • 20 J
    • 50 J
    • 100 J
  10. A 2 kg object is dropped through 10 m with g = 9.8 m s^-2 and no air resistance. How much gravitational potential energy does it lose?

    • 19.6 J
    • 2 J
    • 196 J
    • 98 J
  11. A device takes in 200 J and gives out 150 J of useful energy. What is its efficiency?

    • 75%
    • 133%
    • 50%
    • 25%
  12. A 30 kg load is lifted at constant speed through 2 m. What is the work done against gravity? Use g = 9.8 m s^-2.

    • 1176 J
    • 60 J
    • 294 J
    • 588 J
  13. A 10 kg box slides 5 m against a friction force of 20 N. What energy is transferred to thermal energy by friction?

    • 200 J
    • 20 J
    • 100 J
    • 50 J
  14. A 0.5 kg ball is dropped from rest through 3 m. Ignoring air resistance and using g = 9.8 m s^-2, what is its speed just before impact?

    • 5.4 m s^-1
    • 7.7 m s^-1
    • 3.0 m s^-1
    • 29.4 m s^-1
  15. A 1.2 kg trolley speeds up from 4 m s^-1 to 8 m s^-1. What work is done on it?

    • 14.4 J
    • 9.6 J
    • 28.8 J
    • 57.6 J
  16. A 50 kg object is pushed at constant speed up a smooth 10 m slope inclined at 30°. What work is done against gravity?

    • 980 J
    • 490 J
    • 4900 J
    • 2450 J
  17. A 2 kg object falls 5 m and reaches the ground at 8 m s^-1. How much energy is transferred to other forms, using g = 9.8 m s^-2?

    • 16 J
    • 34 J
    • 98 J
    • 64 J
  18. The area under a force-displacement graph gives the work done. A force rises uniformly from 0 to 10 N over 4 m. What is the work done?

    • 20 J
    • 40 J
    • 10 J
    • 5 J
  19. A motor with 75% efficiency lifts a 20 kg load through 5 m. What input energy is needed to lift the load, using g = 9.8 m s^-2?

    • 980 J
    • 735 J
    • 1300 J
    • 1960 J
  20. A car of kinetic energy 2 x 10^5 J is brought to rest by a constant braking force of 4 x 10^4 N. What distance does it travel before stopping?

    • 50 m
    • 5 m
    • 0.2 m
    • 8 m

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