An object moving in a circular path at constant speed 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:

The angular speed of the seconds needle in a mechanical watch is:

$A$ particle is moving in a circle with uniform speed. Its motion is

An annular ring with inner and outer radii $R_{1}$ and $R_{2}$ is rotating with a uniform angular speed $\omega$ about its central axis. The ratio of the centripetal forces experienced by two particles of equal mass $m$ situated on the inner and outer parts of the ring,$\frac{F_{1}}{F_{2}}$ is

$A$ ball is moving uniformly in a circular path of radius $1 \, m$ with a time period of $1.5 \, s$. If the ball is suddenly stopped at $t = 8.3 \, s$,the magnitude of the displacement of the ball with respect to its position at $t = 0 \, s$ is closest to .......... $m$.