Why Aristotle’s “law of motion” was discredited, Newton’s three laws, F = ma, action and reaction, and applications such as seat belts, rockets, sprinklers and terminal velocity.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Push a book across a table and it stops. Aristotle thought force is needed to keep things moving. Newton explained that the book stops only because friction acts on it.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Velocity ∝ force; discredited because friction was ignored.
A body stays at rest or at constant velocity unless a resultant force acts (inertia).
F = ma (resultant force); a ∝ F; a ∝ 1/m.
Equal and opposite forces, acting on DIFFERENT bodies.
Resistance to change of motion; bigger mass, more inertia.
1 N = 1 kg m/s².
Resultant force zero: air resistance = weight.
Seat belts (N1), rockets and sprinklers (N3), trampolines (N3).
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Physics Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
A car of mass 1 500 kg travels along a straight level road. The engine produces a forward force of 4 000 N and the resistive forces total 1 000 N.
(a) (a) State Newton’s second law of motion. [2]
(b) (b) Calculate the resultant force on the car. [2]
(c) (c) Calculate the acceleration of the car. [3]
(d) (d) The car reaches a speed at which the resistive forces equal the engine force. Describe its motion afterwards, and name this law. [2]
(e) (e) State Newton’s third law and give one example. [3]
(f) (f) Explain why a passenger without a seat belt moves forward when the car brakes suddenly. [3]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.