A gardener pushes a lawn-mower on a level lawn by applying a constant force of at an…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A gardener pushes a lawn-mower on a level lawn by applying a constant force of 200N at an angle θ to the horizontal while the mower moves in a straight line.
(i) Define work and state its SI unit.
(ii) Explain qualitatively how the sign and magnitude of the work done by the gardener change as θ varies from 0∘ to 180∘. State the ranges of θ for which the work is (a) positive, (b) zero and (c) negative.
(iii) If the mower is pushed through 10m with θ=60∘, calculate the numerical value of the work done. Would this work increase or decrease if the angle were reduced to 30∘ while all other quantities remain the same? Give a brief reason.