OCR A Level Physics A
OCR A Level Physics A Module 3: Forces and Motion Exam Questions
Free OCR A Level Physics A exam questions for Module 3: Forces and Motion, with a mark scheme for every pack. Covers kinematics and projectiles, forces, moments and equilibrium, work, energy and power, materials and the Young modulus, Newton's laws and momentum.
Module 3: Forces and Motion exam questions
5 question packs of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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A-Level Physics Flashcards for 2027 Onwards
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Then test yourself with the questions on this page.
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About OCR A Level Physics A Module 3: Forces and Motion
Module 3 of OCR A Level Physics A, Forces and Motion, covers classical mechanics and the behaviour of materials. It includes motion graphs and the suvat equations, projectile motion, drag and terminal velocity, moments, couples and equilibrium, pressure and upthrust, conservation of energy, power and efficiency, Hooke's law and the Young modulus, and Newton's laws with momentum and impulse. It underpins circular motion, oscillations and gravitational fields in Module 5. Examiners frequently test projectile problems, triangle of forces, stress-strain graphs, the Young modulus practical, and conservation of momentum in collisions and explosions.
What you need to know
- 3.1 Displacement, velocity and acceleration, motion graphs, the suvat equations, free fall and determining g, stopping distances, and projectile motion with independent components.
- 3.2 Weight, drag, upthrust and friction, terminal velocity, moments, couples and torque, the principle of moments, triangle of forces, density and pressure p = h rho g.
- 3.3 Work done W = Fx cos(theta), conservation of energy, kinetic and gravitational potential energy, power P = Fv and efficiency.
- 3.4 Hooke's law, force-extension graphs and elastic potential energy, stress, strain and the Young modulus, and the behaviour of ductile, brittle and polymeric materials.
- 3.5 Newton's three laws, momentum, net force as rate of change of momentum, impulse as area under a force-time graph, and conservation of momentum in one and two dimensions.
Common mistakes in Module 3: Forces and Motion
- Using the full velocity in both directions for a projectile. Resolve the launch velocity: the horizontal component stays constant while only the vertical component changes due to g.
- Saying a body at terminal velocity has no forces on it. Forces are balanced, so the resultant force is zero, but weight and drag still act.
- Calculating the Young modulus from load and extension directly. Convert to stress (F / A) and strain (extension / original length) first, using the cross-sectional area from the diameter.
- Treating kinetic energy as conserved in all collisions. Momentum is always conserved in a closed system; kinetic energy is only conserved in elastic collisions.
- Giving Newton's third law pairs as weight and normal contact force on the same object. Third law pairs act on different objects and are the same type of force.
Try three Module 3: Forces and Motion exam-style questions
1. A wire of original length 2.0 m and diameter 0.50 mm extends by 2.0 mm under a load of 50 N. Calculate the Young modulus. (3 marks)
Show the mark scheme answer
A = pi x (0.25 x 10^-3)^2 = 1.96 x 10^-7 m2; stress = 50 / 1.96 x 10^-7 = 2.55 x 10^8 Pa and strain = 2.0 x 10^-3 / 2.0 = 1.0 x 10^-3; E = 2.55 x 10^11 Pa.
2. A 2.0 kg trolley moving at 3.0 m s-1 collides with and sticks to a stationary 1.0 kg trolley. Calculate their common velocity and the kinetic energy lost. (4 marks)
Show the mark scheme answer
Momentum before = 2.0 x 3.0 = 6.0 kg m s-1; v = 6.0 / 3.0 = 2.0 m s-1; KE before = 9.0 J and KE after = 6.0 J; KE lost = 3.0 J.
3. Explain why a skydiver reaches terminal velocity. (3 marks)
Show the mark scheme answer
Initially weight is greater than drag so the skydiver accelerates; drag increases with speed; when drag equals weight the resultant force is zero so acceleration is zero and speed is constant.
Module 3: Forces and Motion FAQs
What does OCR A Level Physics A Module 3: Forces and Motion cover?
Motion, forces in action, work, energy and power, materials, and Newton's laws of motion and momentum.
Which papers is Module 3 examined in?
It is assessed in Paper 1 (Modelling physics) and Paper 3 (Unified physics); it is also assessed at AS.
Which practicals link to Forces and Motion?
Common practicals include determining g by free fall, measuring terminal velocity, and finding the Young modulus of a metal wire.
