In a sinusoidal wave,the time required for a particular point to move from maximum displacement to zero displacement is $0.170 \,s$. The frequency of the wave is ........ $Hz$.

If $A$ and $B$ are any two sets,then $(A \cup B)'$ is equal to

The strongest reducing agent among the following is:

The mass of a planet is half that of the earth and the radius of the planet is one-fourth that of earth. If we plan to send an artificial satellite from the planet,the escape velocity will be,(escape velocity on earth $v_e = 11 \ km \ s^{-1}$) (in $km \ s^{-1}$)

$A$ stationary horizontal disc is free to rotate about its axis. When a torque is applied on it,its kinetic energy as a function of $\theta$,where $\theta$ is the angle by which it has rotated,is given as $K \theta^2$. If its moment of inertia is $I$,then the angular acceleration of the disc is:

$A$ fireman of mass $60 \, kg$ slides down a pole. He is pressing the pole with a force of $600 \, N$. The coefficient of friction between the hands and the pole is $0.5$. With what acceleration will the fireman slide down (in $, m/s^2$)? (Take $g = 10 \, m/s^2$)