Question

A gardener pushes a lawn roller through a distance $20\,m$ . If he applies a force of $20\,kg\,wt$ in a direction inclined at $60^{\circ}$ to the ground, the work done by him is

• A. $1960\,J$
• B. $196\,J$
• C. $1.96\,J$
• D. $196\,kJ$

Answer 1

Answer: (A)

$1960\,J$

Answer 2

Given, $F=20\, kg -w t=20 \times 9.8 \,N$
$\theta=60^{\circ}$ and $s=20\, m$
Work done $=F . s \cos \theta$
$=20 \times 9.8 \times 20 \times \cos 60^{\circ}$
$=1960\, J$