Laws of Motion Questions

A person of mass $60\text{kg}$ is inside a lift of mass $940\text{kg}$ and presses the button on the control panel. The lift starts moving upwards with an acceleration $1.0{\text{m/s}}^2$. If $g=10{\text{ms}}^{-2}$, the tension in the supporting cable is:

A body of mass $M$ hits normally a rigid wall with velocity $V$ and bounces back with the same velocity. The impulse experienced by the body is:

A person is standing in an elevator. In which situation he finds his weight less?

A $0.5\text{kg}$ ball moving with a speed of $12\text{m/s}$ strikes a hard wall at an angle of $30^{\circ }$ with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for $0.25\text{s}$, the average force acting on the wall is:

The mass of a lift is $2000\text{kg}$. When the tension in the supporting cable is $28000\text{N}$, then its acceleration is:

The force ‘F’ acting on a particle of mass ‘m’ is indicated by the force-time graph shown below. The change in momentum of the particle over the time interval from zero to $8\text{s}$ is:

A balloon with mass ‘m’ is descending down with an acceleration ‘a’ (where $a<g$). How much mass should be removed from it so that it starts moving up with an acceleration ‘a’?

A body of mass ($4m$) is lying in $x-y$ plane at rest. It suddenly explodes into three pieces. Two pieces, each of mass ($m$) move perpendicular to each other with equal speeds ($v$). The total kinetic energy generated due to explosion is:

A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches $30^{\circ }$, the box starts to slip and slides $4.0\text{m}$ down the plank in $4.0\text{s}$. The coefficients of static and kinetic friction between the box and the plank will be, respectively: