The angular separation between the minute hand and the hour hand of clock 40 minutes passed after $12 \mathrm{p} . \mathrm{m}$. is

A string of length $L$ is fixed at one end and carries a mass m at the other end. The string makes $\frac{3}{\pi}$ revolutions per second around the vertical axis through the fixed end. The tension in the string is

Which one of the following statements is false for a particle moving in a circle with constant angular speed?

In case of well of death which is a vertical cylindrical wall of radius ' $r$ ' inside which vehicle is driven in horizontal circles. If ' $m$ ' is mass of vehicle, ' $V$ ' is the velocity and ' $\mu_s$ ' is the coefficient of static friction between the wheels of vehicle and walls then correct relation is [ $\mathrm{g}=$ acceleration due to gravity]