$A$ disc rotating about its axis with angular speed $\omega_{o}$ is placed lightly (without any translational push) on a perfectly frictionless table. The radius of the disc is $R$. What are the linear velocities of the points $A, B$ and $C$ on the disc shown in Figure? Will the disc roll in the direction indicated?

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) The angular speed of the disc is $\omega_{o}$ and its radius is $R$. The linear velocity $v$ of a point at a distance $r$ from the center is given by $v = r \omega_{o}$.
For point $A$ (at distance $R$ from the center,at the top): $v_{A} = R \omega_{o}$,directed tangentially to the right.
For point $B$ (at distance $R$ from the center,at the bottom): $v_{B} = R \omega_{o}$,directed tangentially to the left.
For point $C$ (at distance $R/2$ from the center): $v_{C} = (R/2) \omega_{o}$,directed tangentially to the right.
The disc will not roll. Rolling motion requires the presence of friction to provide the necessary torque and to satisfy the condition $v_{cm} = R \omega$. Since the table is perfectly frictionless,there is no external force to cause translational motion of the center of mass,and thus the disc will simply continue to rotate about its stationary center.

Explore More

Similar Questions

$A$ uniform solid cylinder of mass $m$ and radius $R$ is set in rotation about its axis with an angular velocity $\omega_0$,then lowered with its lateral surface onto a horizontal plane and released. The coefficient of friction between the cylinder and plane is equal to $\mu$. The time after which the cylinder starts rolling without slipping is

Difficult
View Solution

Consider a point $P$ on the circumference of a disc rolling along a horizontal surface. If $R$ is the radius of the disc,the distance through which $P$ moves in one full rotation of the disc is:

Difficult
View Solution

The speed of rolling of a ring of mass $M$ changes from $V$ to $3\ V$. What is the change in its kinetic energy (in $,MV^2$)?

$A$ string is wound around a hollow cylinder of mass $5\, kg$ and radius $0.5\, m$. If the string is now pulled with a horizontal force of $40\, N$,and the cylinder is rolling without slipping on a horizontal surface (see figure),then the angular acceleration of the cylinder will be ......... $rad/s^2$. (Neglect the mass and thickness of the string)

$A$ solid sphere is rolling on a horizontal plane without slipping. If the ratio of angular momentum about the axis of rotation of the sphere to the total energy of the moving sphere is $\pi: 22$,then the value of its angular speed will be $...........\,rad/s$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo