Forces and Motion Exam Questions for IGCSE Physics

This guide covers the high-mark question types in the forces and motion section of IGCSE Physics, the largest topic in the syllabus.

Question type 1: Speed, velocity and acceleration

Calculate using v = d/t and a = (v - u)/t. Convert units (km/h to m/s: divide by 3.6).

Worked example: A car accelerates from 10 m/s to 30 m/s in 5 s. Calculate the acceleration.

a = (v - u) / t = (30 - 10) / 5 = 20 / 5 = 4 m/s^2.

Question type 2: Distance-time and velocity-time graphs

Distance-time: gradient = speed. Flat section = stationary.

Velocity-time: gradient = acceleration. Area under graph = distance. Flat section = constant velocity.

Question type 3: Newton’s laws

Apply F = ma to calculate force, mass or acceleration. Explain motion in terms of balanced and unbalanced forces.

Question type 4: Moments

Calculate moments using moment = F x d. Apply the principle of moments for equilibrium (clockwise = anticlockwise).

Worked example: A 50 N force acts at 0.4 m from a pivot. What force at 0.8 m on the other side balances it?

50 x 0.4 = F x 0.8. F = 20 / 0.8 = 25 N.

Question type 5: Energy conservation

Use Ek = 0.5mv^2 and Ep = mgh. Show that energy is conserved: Ep lost = Ek gained (ignoring friction).

Question type 6: Momentum (Extended)

Use p = mv and conservation of momentum: total momentum before = total momentum after.

Practice approach

This section has the most marks in the exam. Do at least 15 past paper questions on forces and motion.