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Work, Energy, and Power — High School Physics practice questions

14 multiple-choice questions and 16 flashcards on Work, Energy, and Power, about 9% of the High School Physics bank. Every one carries a written rationale.

Written and maintained by the CoStudy team · last updated 2026-10-12 · how we write and review questions

What this chapter covers

Work, Energy, and Power is one of 11 chapters in CoStudy's High School Physics bank, and it holds 14 of the bank's 150 multiple-choice questions — roughly 9% of the total. That proportion is not arbitrary: chapters follow the certifying body's published exam outline, and the number of questions in each is set by that domain's published weight, so the share of your practice time this chapter takes matches the share of the real exam it accounts for.

Studying by chapter is worth doing once you have a diagnostic score. A single overall percentage tells you whether you are close; it does not tell you which domain is dragging. Working a weak chapter in isolation, and re-testing it in isolation, is the fastest way to move a score that has stalled — and it is why the mock exams in CoStudy report by domain rather than as one number.

Free Work, Energy, and Power practice questions

7 questions drawn from this chapter, with the full rationale shown — the controlling principle behind the right answer, and why each wrong option tempts and fails.

A 50 N force pushes a box 4 m in the direction of the force. How much work is done?

  1. 12.5 J
  2. 54 J
  3. 200 J
  4. 46 J

Answer: C — 200 J

C) Correct — W = Fd = 50 × 4. A) Divides instead of multiplying. B) Adds. D) Subtracts.

What is the gravitational potential energy of a 2 kg book 5 m above the floor? (g = 9.8 m/s²)

  1. 10 J
  2. 49 J
  3. 98 J
  4. 16.8 J

Answer: C — 98 J

C) Correct — PE = mgh = 2 × 9.8 × 5. A) Leaves out g. B) Includes an extra ½. D) Adds the numbers.

What is the kinetic energy of a 2 kg ball moving at 3 m/s?

  1. 6 J
  2. 18 J
  3. 3 J
  4. 9 J

Answer: D — 9 J

D) Correct — KE = ½mv² = ½(2)(9). A) Computes mv, which is momentum. B) Leaves out the ½. C) Computes ½mv.

A machine takes in 100 J and delivers 80 J of useful work. Its efficiency is:

  1. 125%
  2. 20%
  3. 80%
  4. 180%

Answer: C — 80%

C) Correct — Efficiency = useful output ÷ input. A) Divides input by output. B) Is the share wasted. D) Adds the numbers.

A motor does 600 J of work in 3 s. What is its power?

  1. 1,800 W
  2. 200 W
  3. 0.005 W
  4. 603 W

Answer: B — 200 W

B) Correct — P = W/t = 600/3. A) Multiplies. C) Divides time by work. D) Adds.

A spring with k = 200 N/m is stretched 0.1 m. How much energy does it store?

  1. 20 J
  2. 2 J
  3. 1 J
  4. 10 J

Answer: C — 1 J

C) Correct — PE = ½kx² = ½(200)(0.01). A) Computes kx, which is the force. B) Leaves out the ½. D) Uses ½kx.

The kilowatt-hour on an electric bill is a unit of:

  1. power
  2. current
  3. voltage
  4. energy

Answer: D — energy

D) Correct — 1 kWh = 3.6 million joules. A) Kilowatts alone measure power. B) Is measured in amperes. C) Is measured in volts.

Work, Energy, and Power flashcards

1 cards from the 16 in this chapter.

Define work in physics.

W = F·d·cos θ. Work is done when a force causes displacement; only the component of force along displacement does work.

Practise the full chapter

These are a sample. The full Work, Energy, and Power chapter runs 30 items with per-chapter progress tracking, on the web and in the iOS app.

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