Rotational MotionHard
Question
A thin uniform rod $(X)$ of mass M and length L is pivoted at a height $\left( \frac{L}{3} \right)$ as shown in the figure. The rod is allowed to fall from a vertical position and lie horizontally on the table. The angular velocity of this rod when it hits the table top, is $\_\_\_\_$ . ( $g =$ gravitational acceleration)
Options
A.$\sqrt{\frac{3}{2}\frac{\text{ }g}{\text{ }L}}$
B.$\frac{3}{\sqrt{2}}\sqrt{\frac{\text{ }g}{\text{ }L}}$
C.$\frac{1}{\sqrt{2}}\sqrt{\frac{\text{ }g}{\text{ }L}}$
D.$\sqrt{\frac{3\text{ }g}{\text{ }L}}$
Solution
$mg\frac{\mathcal{l}}{6} = \frac{1}{2}I\omega^{2}$
Here $I = \frac{m\mathcal{l}^{2}}{12} + \frac{m\mathcal{l}^{2}}{36} = \frac{m\mathcal{l}^{2}}{9}$
$${mg\frac{\mathcal{l}}{6} = \frac{m\mathcal{l}^{2}}{18}\omega^{2} \Rightarrow \omega^{2} = \frac{3\text{ }g}{\mathcal{l}} }{\omega = \sqrt{\frac{3\text{ }g}{\mathcal{l}}}}$$
Create a free account to view solution
View Solution FreeMore Rotational Motion Questions
A thin rod of length 4l, mass 4m is bent at the points as shown in the fig. What is the moment of inertia of the rod abo...A disc of mass M and radius R rolls on a horizontal surface and then rolls up an inclined plane as shown in the figure. ...Off two eggs which identical sizes, shapes and weights, one is raw and the other is half - billed. The ratio between the...In the figure, the blocks have unequal masses m1 and m2 (m1 > m2). m1 has a downward acceleration a. The pulley P has...In the following figure r1 and r2 are 5 cm and 30 cm respectively. If the moment of inertia of the wheel is 5100 kg-m2 t...