Question

A body is moving along a circle of radius $r$ under the influence of centripetal force $F$. Its total energy is

• A. $rF$
• B. $-rF$
• C. $\frac{rF}{2}$
• D. $\frac{-rF}{2}$

Answer 1

The correct option is D $\frac{-rF}{2}$

The body is bound to rotate in the circle hence its energy will be negative
Centripetal force $F=\frac{m{V}^2}{r}=m{w}^{2}r$ because $V=wr$ , w is angular velocity.
$F=\frac{-dU}{dr}$

Taking kind of force is obeys inverse square law.
Potential energy will be $P.E=-m{v}^2$
Total energy $=K.E+P.E=-\left(m{v}^2\right)/2=\frac{-rF}{2}$