A man of mass 60 kg is standing in a lift moving up with a retardation of $2.8 \mathrm{~ms}^{-2}$. The apparent weight of the man is

The initial and final velocities of a body projected vertically from the ground are $20 \mathrm{~ms}^{-1}$ and $18 \mathrm{~ms}^{-1}$ respectively. The maximum height reached by the body is (Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

A particle is acted upon by a force of constant magnitude such that its velocity and acceleration are always perpendicular to each other, then its

If the moment of inertia of a uniform solid cylinder about the axis of the cylinder is $\frac{1}{n}$ times its moment of inertia about an axis passing through its midpoint and perpendicular to its length, then the ratio of the length and radius of the cylinder is