question_answer

A uniform rod of mass m and length I is held inclined at an angle of \[{{60}^{o}}\] with the vertical. What will be the potential energy of the rod in this position?

A)  Zero             

B)  \[\frac{mgl}{4}\]

C)  \[\frac{mgl}{2}\]

D)  \[mgl\]

Correct Answer: C

Solution :

Vertical height \[=h=l\,\cos {{60}^{o}}\] and        potential energy = mgh \[mgl\cos {{60}^{o}}\] \[=\frac{mgl}{2}\]