Question

A stick of mass $m$ and length $l$ is pivoted at one end and is displaced through an angle $\theta$. The increase in potential energy is

• A. $m g \frac{l}{2}(1-\cos \theta)$
• B. $m g \frac{l}{2}(1+\cos \theta)$
• C. $m g \frac{l}{2}(1-\sin \theta)$
• D. $m g \frac{l}{2}(1+\sin \theta)$

Answer 1

Answer: (A)

Using mechanical energy conservation
$U=\frac{m g l}{2}(1-\cos \theta)$