Question

A gardener pushes a lawn roller through a distance of 20m. If he applies a force of 20kg weight in a direction inclined at 60° to the ground, find the work done by him. (g=9.8m/s^2)

(a) 400J

(b) 1960J

(c) 250J

(d) 2514J

This question was posed to me during an internship interview.

Question is taken from Work, Energy and Power topic in section Nature of Physical World of Engineering Physics I

Answer 1

Correct option is (b) 1960J

For explanation: F = 20kg wt = 20×9.8N

s = 20m

θ = 60°

W = Fscosθ = 20×9.8×20×cos⁡60°

W = 1960J.