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S4 Physics Work, Energy and Power Practice Paper 1 | W = Fs, Kinetic and Potential Energy, Power – 10 Questions with Answers
S4 Physics Work, Energy and Power Practice Paper 1 | W = Fs, Kinetic and Potential Energy, Power – 10 Questions with Answers
Ten work and energy questions, from W = Fs to kinetic and potential energy interchange, power and efficiency, each with an answer and a one-line explanation.
Direct answers This paper has 10 questions covering work, conservation of energy, power and efficiency; suggested time 20 minutes.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 minutes |
| Difficulty mix | Foundation 3 · Intermediate 4 · Challenge 2 · Error redo 1 |
| Chapter | S4 Physics: Work, Energy and Power |
| Level | S4 (DSE) |
02 Questions (10 items)
- FoundationA box is pushed 4 m along a horizontal floor by a horizontal force of 50 N. How much work is done?
- FoundationA ball of mass 2 kg moves at 3 m/s. What is its kinetic energy?
- FoundationA 5 kg object is lifted 2 m (g = 10 m/s^2). How much gravitational potential energy does it gain?
- IntermediateA machine does 600 J of work in 20 s. What is its power?
- IntermediateA machine takes in 300 J and gives out 240 J of useful energy. What is its efficiency?
- IntermediateA 1 kg ball falls freely from a height of 5 m with no air resistance. What are its kinetic energy and speed when it reaches the ground?
- IntermediateA crane lifts a 20 kg load 5 m at constant speed in 10 s (g = 10 m/s^2). What are the work done and the power?
- ChallengeA 60 N object is pushed up a 3 m long slope to a height of 1 m, friction neglected. What is the ideal pushing force?
- ChallengeA 0.5 kg ball is thrown upwards at 20 m/s (g = 10 m/s^2). How high can it rise?
- Error redoIs the statement ‘a large power means a large amount of work has been done’ correct?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | W = Fs = 50 * 4 = 200 J. | The force and the displacement point the same way, so the two values multiply directly. |
| 2 | KE = 1/2 mv^2 = 1/2 * 2 * 3^2 = 9 J. | Kinetic energy is proportional to the square of the speed. |
| 3 | dPE = mgh = 5 * 10 * 2 = 100 J. | The potential energy gained comes from the work done in lifting it. |
| 4 | P = W / t = 600 / 20 = 30 W. | Power measures how fast work is done. |
| 5 | Efficiency = 240 / 300 * 100% = 80%. | The other 60 J is lost as heat or sound. |
| 6 | KE = mgh = 1 * 10 * 5 = 50 J, v = sqrt(2 * 10 * 5) = 10 m/s. | All the potential energy becomes kinetic energy. |
| 7 | W = 20 * 10 * 5 = 1 000 J, P = 1 000 / 10 = 100 W. | Lifting at constant speed means the pulling force equals the weight. |
| 8 | Work needed = 60 * 1 = 60 J, so the force = 60 / 3 = 20 N. | A slope reduces the force needed but not the work done. |
| 9 | KE = 1/2 * 0.5 * 20^2 = 100 J, h = 100 / (0.5 * 10) = 20 m. | All the kinetic energy becomes gravitational potential energy. |
| 10 | No. A large power only means work is done quickly; the total work done also depends on how long it takes. | P = W / t, so all three quantities are needed. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Read the S4 Physics: Work, Energy and Power chapter notes first, then work through all ten questions and mark them against the answers.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
