(a) Define power and state its SI unit. (b) A gardener pushes a lawn-mower along a…

PHYSICS · Subjective · CBSE · Physics · Work and Energy · Work and Energy

Problem

(a) Define power and state its SI unit. (b) A gardener pushes a lawn-mower along a horizontal lawn with a constant horizontal force of 60 N60\,\text{N} so that it moves at a steady speed of 1.5 m s−11.5\,\text{m\,s}^{-1}. Without doing any numerical calculation, explain how the power developed by the gardener will change if the speed is doubled while the force remains the same. Give a reason for your answer based on the relationship between the relevant physical quantities.

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