Question

A gardener pushes a lawn roller through a distance of 20 m. If he applies a force of 30 kg-wt in a direction inclined at 60° to the ground, the work done by the gardener in pushing the roller is ______.

`["g" = 9.8  "m""/""s"^2, sin30^circ = cos60^circ = 1/2, cos30^circ = sin60^circ = sqrt3/2]`

Options

• 2460 J

• 3640 J

• 3940 J

• 2940 J

Answer 1

A gardener pushes a lawn roller through a distance of 20 m. If he applies a force of 30 kg-wt in a direction inclined at 60° to the ground, the work done by the gardener in pushing the roller is 2940 J.

Explanation:

Given, force, F = 30 kg-wt = 30 × 9.8 N

s = 20 m, θ = 60°

∴ Work done, W = Fs cosθ

= 30 × 9.8 × 20 × cos60° = 2940 J