(a) Define the term ‘work’. Write the formula for the work done on a body when a force acts on the body in the direction of its displacement. Give the meaning of each symbol which occurs in the formula. (b) A person of mass $50\ kg$ climbs a tower of height $72\ metres$. Calculate the work done. $(g=9.8\ ms^{-2})$

(a). Work: When a force is applied upon an object and the object moves due to force, then it is said to be work done.

Formula for the work done:

$\boxed{W=Fd\cos\theta}$

Here, $W\rightarrow$work done

$F\rightarrow$ Force acted on the object

$d\rightarrow$displacement in the body

$\theta\rightarrow$ angle between the directions of force and the displacement.

The SI unit of work is Joule.

(b). Mass of the person $m=50\ kg$

Gravitational acceleration $g=9.8\ m/s^2$

Height $h=72\ m$

Therefore, work done to climb the tower $W=mgh$

$=50\ kg.\times9.8\ m/s^2\times 72\ m$

$=35,280\ J$

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Updated on: 10-Oct-2022

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