If a body moving in a circular path maintains a constant speed of $10 \,ms^{-1}$, then which of the following correctly describes the relation between acceleration $(a)$ and radius $(r)$?

$A$ body is moving with a uniform speed of $20 \,m/s$ on a horizontal circle. The change in velocity of the body in half a revolution is

$A$ particle revolving in a circular path travels the first half of the circumference in $4 \ s$ and the next half in $2 \ s$. What is its average angular velocity?

$A$ motorcyclist going round in a circular track at a constant speed has:

What is the direction of instantaneous velocity for an angular path?

For a particle in uniform circular motion,the acceleration $\vec{a}$ at any point $P (R, \theta)$ on the circular path of radius $R$ is (when $\theta$ is measured from the positive $x$-axis and $v$ is uniform speed):