Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it.How much work is done in just holding it?` (Take g=10ms^(-2)).`

Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it. How much work is done by men in lifting the box?

The power of a motor pump is 5 kW. How much water per minute the pump an raise to height of 20 m ? Take g = 10ms ^-2 .

A coolie lifts a box of 15 kg from the ground the a height of 2m. Calculate the work done by the coolie on the box.

A fighter plane flying horizontally at an altitude of 1.5 km with speed 720 km//h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed 600 m s^-1 to hit the plane ? At what minimum altitude should the pilot fly the plane to avoid being hit ? (Take g = 10 ms^2 ).

Find the work done in lifting a 50 kg bucket a water through a vertical height of 2 m.

An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy ? If the object is allowed to fall, find its kinetic energy when it is half-way down. Take g = 10 ms ^-2 .

A tank of capacity 10^3 kg is placed at the top of a house 10 m high.This tank is filled by a motor in 30 minutes by lifting water from a 20 m deep well.Find the power of motor(Take g=10m s^(-2) .

If a man lifts a load up with the help of rope such that it raises the load of mass 50 kg to a height of 20 m in 100 seconds. Find the power of man. (Take g = 10ms^-2 )

Find the magnitude of electron field which just balances a deuteron of mass 3.2 xx 10^-27 kg . (Take g = 10 ms^-2).