First slide

Rotational motion

Question

A rod of length 50cm is pivoted at one end. It is raised such that it makes an angle 30⁰ from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in rad/s ) will be ( g=10m/s²)

Moderate

Solution

According to Law of Conservation of Energy
$\begin{array}{l} \Rightarrow m g \frac{l}{2} \sin 30 = \frac{1}{2} I ω^{2} \\ \Rightarrow m g \frac{l}{2} \frac{1}{2} = \frac{1}{2} \frac{m l^{2}}{3} ω^{2} \\ \Rightarrow ω = \sqrt{\frac{3 g}{2 l}} = \sqrt{30} = 5.48 rad / s \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App