Question

How much is the mass of a man if he has to do 2500 joules of work in climbing a tree 5 m tall? (g = 10 m s⁻²)

Answer 1

Work done in climbing or potential energy, (P.E) = 2500 J
Acceleration due to gravity, (g) = 10 m/s²
Height above the ground be, (h) = 5 m
Let the mass of the man be (m)
We have a relation as,
P.E = m × g × h
So, mass can be calculated as,
$m=\frac{P.E}{h\times g}$
So, mass of the man,
$$\begin{gathered} m=\frac{2500}{5\times 10}\mathrm{kg} \\ =\frac{250}{5}\mathrm{kg} \\ =\boxed{50\mathrm{kg}} \end{gathered}$$