The magnitude of the centripetal force acting on a body of mass $m$ executing uniform circular motion in a circle of radius $r$ with speed $v$ is:

$A$ body is moving along a circular track of radius $100 \ m$ with velocity $20 \ m/s$. Its tangential acceleration is $3 \ m/s^{2}$,then its resultant acceleration will be (in $m/s^{2}$)

$A$ particle is moving in a circular path of radius $r$ under the action of a force $F$. If at an instant the velocity of the particle is $\vec{v}$,and the speed of the particle is increasing,then:

The acceleration of a train travelling with a speed of $400 \, m/s$ as it goes round a curve of radius $160 \, m$ is:

$A$ cyclist is riding with a speed of $27 \; km/h$. As he approaches a circular turn on the road of radius $80 \; m$,he applies brakes and reduces his speed at the constant rate of $0.50 \; m/s^2$. What is the magnitude and direction of the net acceleration of the cyclist on the circular turn?

$A$ car is travelling with linear velocity $v$ on a circular road of radius $r$. If it is increasing its speed at the rate of $a \ m/s^2$,then the resultant acceleration will be