Friction and inclined planes quiz for A Level physics: 10 questions with answers

Quick answer: Newton's second law states that the resultant force equals mass times acceleration, ΣF = ma. This Physics 11-12 quiz checks friction and inclined planes with 10 multiple-choice questions and instant feedback; every answer comes with a short explanation.

Choose the best answer for each of the ten questions. Picture the forces on the object and decide which direction is positive before you look at the options. Then read the explanations to find out why the other choices are wrong.

Level: Physics grades 11-12 (A Level · IB · Class 11-12) · Curriculum: IB A.2

A 10 kg object has a resultant force of 25 N. What is its acceleration?

What is the normal reaction on a 5.0 kg block on a level table?

A 20 kg crate slides on a floor with μk = 0.25. What is the friction force?

On a slope of angle θ, the normal reaction on a block of mass m is:

A frictionless slope makes an angle of 30° with the horizontal. What is the acceleration of a block sliding down?

A block just slips on a board tilted at 35°. What is μs?

What happens to the acceleration of a block on a rough slope if you double its mass?

A taut string joins two blocks, and you pull them along. Which quantity is the same for both?

A person of mass 80 kg stands in a lift moving upwards at constant speed. What is the scale reading?

Why is the friction force on a locked-wheel skid usually smaller than the maximum static friction?

State Newton's second law — ΣF = ma

Weight formula — W = mg, with g = 9.81 N/kg

Friction limit formula — f ≤ μN

Normal reaction on a slope — N = mg cos θ

Driving force down a slope — mg sin θ

Acceleration down a rough slope — a = g(sin θ − μ cos θ)

Coefficient from slipping angle — μs = tan θ

What is shared by connected bodies? — The acceleration (taut string)

Lift accelerating up: scale reading — N = m(g + a)

Which is larger: μs or μk? — Normally μs