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Newton's Laws of Motion and Forces — High School Physics practice questions

14 multiple-choice questions and 17 flashcards on Newton's Laws of Motion and Forces, 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

Newton's Laws of Motion and Forces 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 Newton's Laws of Motion and Forces 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 20 N net force acts on a 4 kg object. What is its acceleration?

  1. 80 m/s²
  2. 0.2 m/s²
  3. 5 m/s²
  4. 16 m/s²

Answer: C — 5 m/s²

C) Correct — a = F/m = 20/4. A) Multiplies. B) Divides mass by force. D) Subtracts.

An object has zero net force acting on it. It must be:

  1. at rest or moving at constant velocity
  2. at rest
  3. slowing down
  4. speeding up

Answer: A — at rest or moving at constant velocity

A) Correct — Zero net force means zero acceleration. B) Could also be moving steadily. C) Would need a net force. D) Would need a net force.

An astronaut travels from Earth to the Moon. Her mass:

  1. and weight both decrease
  2. stays the same, but her weight decreases
  3. decreases, but her weight stays the same
  4. and weight both stay the same

Answer: B — stays the same, but her weight decreases

B) Correct — Mass is the amount of matter; weight depends on gravity. A) Mass doesn't change. C) Reverses the two. D) Weight depends on gravity.

Compared with kinetic friction, maximum static friction between two surfaces is usually:

  1. smaller
  2. always equal
  3. zero
  4. greater

Answer: D — greater

D) Correct — It takes more force to start sliding than to keep sliding. A) Reverses the usual relationship. B) They usually differ. C) Static friction holds objects in place.

Newton's first law states that an object keeps its motion unless:

  1. it runs out of energy
  2. a net force acts on it
  3. it is very heavy
  4. time passes

Answer: B — a net force acts on it

B) Correct — This is the law of inertia. A) Motion doesn't need energy to continue. C) Mass resists change but doesn't stop motion. D) Time alone doesn't change motion.

What is the weight of a 50 kg person on Earth? (g = 9.8 m/s²)

  1. 490 N
  2. 50 N
  3. 5.1 N
  4. 59.8 N

Answer: A — 490 N

A) Correct — W = mg = 50 × 9.8. B) Gives the mass as the weight. C) Divides mass by g. D) Adds instead of multiplying.

A book rests on a level table. The normal force on it:

  1. is greater than its weight
  2. is zero
  3. is less than its weight
  4. equals its weight

Answer: D — equals its weight

D) Correct — No other vertical forces act. A) Would accelerate it upward. B) The table supports it. C) Would accelerate it downward.

Newton's Laws of Motion and Forces flashcards

4 cards from the 17 in this chapter.

What is friction?

A force that opposes relative motion (or tendency of motion) between surfaces in contact.

What is the formula for kinetic friction?

f_k = μ_k N, where μ_k is the coefficient of kinetic friction.

Why is μ_s typically larger than μ_k?

Because more force is needed to start motion than to maintain it (microscopic bonds form when surfaces are at rest).

What is inertia?

An object's resistance to changes in its state of motion. Mass is a measure of inertia.

Practise the full chapter

These are a sample. The full Newton's Laws of Motion and Forces chapter runs 31 items with per-chapter progress tracking, on the web and in the iOS app.

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