The work done in moving a body of mass $2 \mathrm{~kg}$ to a height of $4 \mathrm{~m}$ from the surface of…
The work done in moving a body of mass $2 \mathrm{~kg}$ to a height of $4 \mathrm{~m}$ from the surface of the earth is
(Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )
$10 \mathrm{~J}$
$20 \mathrm{~J}$
$40 \mathrm{~J}$
$80 \mathrm{~J}$
Solution
Mass of body, M=2 kg
Height, $\mathrm{H}=4 \mathrm{~m}$
work done to lift a body = potential energy of body
$
\begin{aligned}
& \therefore W=m g h=2 \times 10 \times 4 \\
& W=80 \mathrm{~J}
\end{aligned}
$