$A$ particle is moving in a circle with uniform speed. It has constant

$A$ particle is moving along a circular path with constant speed and centripetal acceleration '$a$'. If the speed is doubled,the ratio of its acceleration after and before the change is:

Find the angle between the velocity vector and the acceleration vector for a particle in uniform circular motion. (in $^{\circ}$)

$A$ merry-go-round rotating at a constant angular speed completes $9$ rotations in $18$ seconds. What is its angular speed?

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

Two particles $A$ and $B$ are moving in uniform circular motion in concentric circles of radii $r_{A}$ and $r_{B}$ with speeds $v_A$ and $v_B$ respectively. The time period of rotation is the same. The ratio of angular speed of $A$ to that of $B$ will be