$A$ train is moving at a speed of $50\, m s^{-1}$ on a curved track of radius $250\, m$. What is its acceleration (in $, m s^{-2}$)?

The acceleration of a body in a non-uniform circular motion is $5\, ms^{-2}$. Which one of the following is correct?

In non-uniform circular motion,the ratio of tangential to radial acceleration is ($r=$ radius,$\alpha=$ angular acceleration,$V=$ linear velocity).

$A$ uniform circular disc of radius $50\, cm$ at rest is free to turn about an axis which is perpendicular to its plane and passes through its centre. It is subjected to a torque which produces a constant angular acceleration of $2.0\, rad \,s^{-2}$. Its net acceleration in $m\,s^{-2}$ at the end of $2.0\,s$ is approximately (in $.0$)

$A$ particle is moving in a circle of radius $R$ with constant speed $v$. If the radius is doubled while keeping the speed the same,what happens to the centripetal force?

For a particle in a uniformly accelerated circular motion: