A person of mass 50kg climbs a tower of height 72m. Calculate the work done.$\left(\mathrm{g}\right)=9.8 \mathrm{m}/{\mathrm{s}}^2$

Work done in moving a body (W) is equal to the product of force exerted on the body (F), and the displacement of the body (s) in the direction of force. 

Mathematically, W = F x s
It has been given that,
Mass of the person m = 50 kg, 
Height climbed by the person h = 72 m and 
Gravitational acceleration $\left(\mathrm{g}\right)=9.8 \mathrm{m}/{\mathrm{s}}^2$. 
Since gravitational pull acts on the person while he is climbing the tower,
$\mathrm{F}=\mathrm{mg}$
$\Rightarrow \mathrm{F}=50\times 9.8\mathrm{ }$
$\Rightarrow \mathrm{F}=490\mathrm{N}$
Therefore, 

$\mathrm{W}=490\times 72$
$\Rightarrow \mathrm{W}=35280 \mathrm{J}$

When a person of mass 50 kg climbs a tower of height 72 m the work done is 35280 J.