Question

A horizontal force acts on a body placed on a smooth horizontal table. If the force applied is $10N$, find the total work done when the displacement of the body is $5m$.

In the above example if the force acts at an angle of $60°$ to the horizontal, find the work done for the same amount of displacement.

Answer 1

Step 1: Given data

1. Force applied (F) = $10N$
2. Displacement of the body (s) = $5m$
3. As the force acts at an angle of $60°$, $\theta$$=60°$

Step 2: Finding work done

case 1: when the angle is zero

Work $=Fs\cos \theta$

$=10\times 5\times \cos 0°$

$=10\times 5\times 1=50J$

case 2 : Work $=Fs\cos \theta$

$=10\times 5\times \cos 60°$

$=10\times 5\times \frac{1}{2}=25J$

Hence, the work done here is $25J$