Question

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

• A. $75°$
• B. $60°$
• C. $45°$
• D. $30°$

Answer 1

The correct option is B

$60°$

Step 1. Given data

Distance moved by body $d=10m$

force on body, $F=5N$

total work done, $W=25J$

Step 2. Finding angle between the force and direction of motion of the body

Work done on a body is given by $W=F.d=Fd\cos \theta$

where $\theta$ is the angle between the force and direction of motion of the body

Putting the values, we get

$$\begin{gathered} 25=5\times 10\times \cos \theta \\ \Rightarrow \cos \theta =\frac{50}{25}=\frac{1}{2} \\ \Rightarrow \theta =60° \end{gathered}$$

Hence, option B is correct.