Question

A girl of mass $50kg$ climbs a flight of $100$ stairs each measuring $0.25m$ in height in $20s$.[Take g=$10\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s^2$}\right.$]

Find work done by the girl.

Answer 1

Given:

Mass=$50kg$

g=$10\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s^2$}\right.$

Height of one stair=$0.25m$

To find the height of $100$ stairs:

Height of $100$stairs=$100\times 0.25=25m$

Formula used:

Work done=$F\times s$

To apply the formula:

W$=mg\times h$

$$\begin{gathered} =50\times 10\times 25 \\ =12500J \end{gathered}$$

Hence, the work done by the girl is $12500J$