AS Daily A Level Physics question
A cyclist tightens a bolt using a 0.10 m Allen key by pushing with a 50 N force at right angles to the key. They then switch to a 0.25 m key and push with the same 50 N at right angles. What is the new turning effect (moment) about the bolt?
Answer
The correct answer is C.
Correct: C — 12.5 N m. Using a longer lever increases the moment in proportion to the perpendicular distance: 50 N × 0.25 m = 12.5 N m. A 5.0 N m — wrongly assumes the moment is unchanged and depends only on force. B 2.0 N m — incorrectly reduces the moment when the distance increases. C 12.5 N m — correct proportional increase from 0.10 m to 0.25 m (factor 2.5). D 25 N m — overestimates, as if doubling again or confusing with a squared dependence.