A boy stands with his hands folded at the cen | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The angular momentum $L$ of the system remains conserved because no external torque acts on the system $(L = I\omega = 	ext{constant})$.The rotat

Vedclass · Accepted Answer

$K/2$

Vedclass · Answer

(B) The angular momentum $L$ of the system remains conserved because no external torque acts on the system $(L = I\omega = 	ext{constant})$.The rotational kinetic energy $K$ is given by $K = \frac{L^2}{2I}$.Since $L$ is constant, we have $K \propto \frac{1}{I}$.Let the initial moment of inertia be $I_1 = I$ and the initial kinetic energy be $K_1 = K$.When the boy stretches his hands, the new moment of inertia becomes $I_2 = 2I$.The new kinetic energy $K_2$ is given by $K_2 = \frac{L^2}{2I_2} = \frac{L^2}{2(2I)} = \frac{1}{2} \left( \frac{L^2}{2I} ight) = \frac{K}{2}$.Therefore, the kinetic energy of the system becomes $K/2$.

$A$ boy stands with his hands folded at the center of a platform rotating about its central axis. The kinetic energy of the system is $K$. The boy now stretches his hands out, which doubles the moment of inertia of the system. The kinetic energy of the system will become

Similar Questions

$Assertion$ : For a system of particles under a central force field,the total angular momentum is conserved.
$Reason$ : The torque acting on such a system is zero.

$A$ thin circular ring of mass $M$ and radius $r$ is rotating about its axis with a constant angular velocity $\omega$. Two objects,each of mass $m$,are attached gently to the opposite ends of a diameter of the ring. The ring will now rotate with an angular velocity:

$A$ person is rotating on a rotating table with an angular speed of $\omega$. He holds two identical masses in his outstretched hands. Without moving his hands,he simply drops the masses. How will his angular velocity change?

$A$ swimmer curls their body before entering the water so that...

$A$ rigid spherical body is spinning around an axis without any external torque. Due to a change in temperature,the volume increases by $1\%$. Its angular speed:

Vedclass Test Series

Exam Paper Generator

Online Exam Module