Contents
Independent final check
Explain without the key
define / calculate / state
Final check
A 0.40 kg trolley moves to the right at 3.0 m/s. (a) Define momentum. (b) Calculate the momentum of the trolley. (c) It hits a 0.20 kg trolley at rest and they stick together. Calculate their velocity. (d) In another collision, the 0.40 kg trolley at 3.0 m/s hits a 0.80 kg trolley at rest and bounces back to the left at 0.20 m/s. Calculate the velocity of the 0.80 kg trolley. (e) State the principle you used in (c) and (d).
define: give the precise meaning. calculate: work out the answer from the data. state: give a concise answer.
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Scope and sources
Cambridge IGCSE Physics 0625 · 2026–2028 v2 · Original learning materials.
Supplement throughout: momentum as mass × velocity, p = mv (1.6.1); impulse as force × the time for which it acts, impulse = FΔt = Δ(mv) (1.6.2); the principle of the conservation of momentum for simple problems in one dimension, including explosions from rest (1.6.3); resultant force as the change in momentum per unit time, F = Δp/Δt (1.6.4), with crumple zones, airbags and seat belts. Kinetic energy and sorting collisions by energy are not used (kinetic energy is in Energy); collisions in two dimensions, Newton’s third law by name and rockets beyond a one-line example are left out. Velocity and acceleration are in Speed and motion graphs, F = ma in Resultant force.
Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.
Official Cambridge syllabus