A small block of mass $m$ slides on a frictionless horizontal table. It is constrained to move inside a ring of radius $l$ which is fixed to the table. At $t=0$, the block has a tangential velocity $v_0$. The coefficient of friction between the block and the ring is $\mu$. The velocity of the block at time $t$ is

 A uniform rod of length $2 \mathrm{m}$. Velocity of point $B$ is $10 \mathrm{m} {\mathrm{s}}^{-1}$ as shown in figure and angular velocity of rod is  $7 \mathrm{rad} {\mathrm{s}}^{-1}$. Then

The figure shows the velocity and acceleration of a point like body at the initial moment of its motion. The acceleration vector of the body remains constant. The minimum radius of curvature of trajectory of the body is

A self-propelled vehicle (assume it as a point mass) runs on a track with constant speed $v$. It passes through three positions $A, B$ and $C$ on the circular part of the track. Suppose $N_A, N_B$ and $N_C$ are the normal forces exerted by the track on the vehicle when it is passing through points $A, B$ and $C$ respectively then