$A$ particle is moving on a circular path of radius $r$ with uniform speed $v$. What is the displacement of the particle after it has described an angle of $60^{\circ}$?

Define angular speed and angular velocity.

The angular speed of a flywheel making $120 \, \text{revolutions/minute}$ is:

Two particles having mass $M$ and $m$ are moving in circular paths having radii $R$ and $r$. If their time periods are the same,then the ratio of their angular velocities will be:

Assertion $(A)$ :- If a body is in a state of uniform circular motion,then its velocity and acceleration both are varying.
Reason $(R)$ :- If the magnitude of velocity is $v$ and the radius of uniform circular motion is $r$,then the magnitude of acceleration is $v^2/r$.

Consider an object making uniform motion around a circle of radius $5 \ m$ with tangential velocity $2 \ ms^{-1}$. The time it takes to complete $2$ revolutions and the magnitude of acceleration respectively are