How a spring stretches under load, the meaning of the limit of proportionality, Hooke’s law F = kx, the spring constant as a gradient, and solving problems on springs and elastic bands.
4 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.
A bathroom scale, a car’s suspension and a trampoline all rely on springs that stretch in proportion to the force applied — until they don’t.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Add load to a spring and compare the extension with the load.
Copy these into your notebook in your own words — that is how they stick.
x = new length − original length.
Within the limit of proportionality, F ∝ x.
F = kx; k in N/m.
The gradient of the straight part of the F–x graph.
Beyond it the graph curves; Hooke’s law no longer applies.
Beyond it the spring does not return to its original length.
Force on y-axis, extension on x-axis, line through the origin.
Extends easily but its graph is not a straight line.
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 spring of original length 12.0 cm is loaded as shown: F = 2.0, 4.0, 6.0, 8.0, 10.0 N gives lengths 14.0, 16.0, 18.0, 20.0, 23.0 cm.
(a) (a) Calculate the extension for each load up to 8.0 N and for 10.0 N. [3]
(b) (b) State the load at which Hooke’s law stops being obeyed. Explain. [2]
(c) (c) Calculate the spring constant in N/cm from the straight part. [3]
(d) (d) Express the spring constant in N/m. [1]
(e) (e) Calculate the length of the spring with a load of 5.0 N, assuming Hooke’s law applies. [3]
(f) (f) Sketch the F–x graph described (label axes and the limit of proportionality). [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.