Question

A force of $20N$ acts on a body and the body moves through $1m$ at an angle of 45${}^o$ to the direction of the force. The work done by the force is

• A. $10\sqrt{2}J$
• B. $\frac{10}{\sqrt{2}}J$
• C. $-10\sqrt{2}J$
• D. $-\frac{10}{\sqrt{2}}J$

Answer 1

The correct option is A $10\sqrt{2}J$

Work done is equal to force into displacement

W = F $\times$ $xCos\theta$ where $x$ = displacement and $\theta$ is the displacement angle

W = 20 $\times$ 1 $\times$ Cos45

= 20 $\times$ $\frac{1}{\sqrt{2}}$ (Since Cos45 = $\frac{1}{\sqrt{2}}$)

= 10$\sqrt{2}$ J