Question

A body moves a distance of $10m$ along a straight line under a action of $5N$ force. If work done is $25J$, then angle between the force and direction of motion of the body will be

• A. $75^{\circ }$
• B. $60^{\circ }$
• C. $45^{\circ }$
• D. $30^{\circ }$

Answer 1

Answer: (B)

Distance $(s)=10m$;
Force $(F)=5N$ and work done $(W)=25J$.
Work done $(W)=Fs\cos \theta =25$
$\therefore 25=5\times 10\cos \theta =50\cos \theta$
or $\cos \theta =25/50=0.5$
or $\theta =60^{\circ }$.