COMEDK 2023 Morning Shift | Rotational Motion Question 1 | Physics

A thin circular ring of mass ,$$M$$ and radius $$R$$ rotates about an axis through its centre and perpendicular to its plane, with a constant angular velocity $$\omega$$. Four small spheres each of mass $$m$$ (negligible radius) are kept gently to the opposite ends of two mutually perpendicular diameters of the ring. The new angular velocity of the ring will be

$$\left(\frac{M+4 m}{M}\right) \omega$$

$$\frac{M}{4 m} \omega$$

$$\left(\frac{M}{M+4 m}\right) \omega$$

$$\left(\frac{M}{M-4 m}\right) \omega$$

COMEDK 2023 Evening Shift

MCQ (Single Correct Answer)

-0

A wheel is free to rotate about a horizontal axis through O. A force of $$200 \mathrm{~N}$$ is applied at a point $$\mathrm{P} 2 \mathrm{~cm}$$ from the center $$\mathrm{O}$$. OP makes an angle of $$55^{\circ}$$ with $$\mathrm{x}$$ axis and the force is in the plane of the wheel making an angle of $$25^{\circ}$$ with the horizontal axis. What is the torque?

4 N m

3.2 N m

2 N m

3.4 N m

COMEDK 2022

MCQ (Single Correct Answer)

-0

A disc of moment of inertia 4 kg - m$$^2$$ revolving with 16 rad/s is placed on another disc of moment of inertia 8 kg - m$$^2$$ revolving 4 rad/s. The angular frequency of composite disc

4 rad/s

$$\frac{3}{16}$$ rad/s

8 rad/s

$$\frac{16}{3}$$ rad/s

COMEDK 2021

MCQ (Single Correct Answer)

-0

Newton's second law of rotational motion of a system particles having angular momentum L is given by

$${{dp} \over {dt}} = {\tau _{ext}}$$

$${{dL} \over {dt}} = {\tau _{{\mathop{\rm int}} }}$$

$${{dL} \over {dt}} = {\tau _{ext}}$$

$${{dL} \over {dt}} = {\tau _{{\mathop{\rm int}} }} + {\tau _{ext}}$$

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