Experiment 3 — Measuring Friction

Topic: Physics · Class 8 · Friction: static, sliding and rolling

Aim: Move the box using a pull of less than 5 newtons .

Daily: Ball bearings in a cycle hub, oil in an engine, and the treads on a tyre are all friction being tuned — reduced where it wastes energy, increased where it gives grip.

Question: Which needs the smallest pulling force for the same box?

Exp: Rolling friction is far smaller than sliding friction.

Exp: Rougher surfaces and heavier loads mean more friction.

Question: Which is largest for the same surfaces?

Exp: Static friction must be overcome before movement starts.

Question: Ball bearings are used to…

Exp: Rolling contact greatly reduces friction.

Question: Which is a useful effect of friction?

Exp: Braking, walking and writing all need friction.