A boy of mass 55kg rus up a filight of 40 stairs, each measuring 0.15m Calculate the work done by the boy.

A boy of mass 40 kgruns up a flight of 50 steps,each of 10 cm high, in 5s, Find the power developed by the boy,

A boy of mass m climbs up the stairs of vertical height h. (a) What is the work done by the boy against the force of gravity ? (b) What would have been the work done if he uses a lift in climbing the same vertical height ?

A crane pulls up a car of mass 500kg to a vertical height of 4m. Calculate the work done by the crane.

A crane pulls up a car of mass 500 kg to a vertical height of 4 m. Calculate the work done by the crane.

A box of 50 kg is lifted by a man of mass 60 kg to a height of 50 m. Calculate the work done by the man.

A man of mass 20 kg is carrying a mass of 3 kg on his head. Calculate the work done by the man in moving a distance of 10 m up an incline of 1 in 5 ?

A boy weighing 50 kg climbs up a vertical height of 100 m. Calculate the amount of work done by him. How much potential energy does he gain ? ( g = 9.8 m//s^(2) ).

A boy of mass 40 kg climbs vertically upwards on a coconut tree to a height of 10m. Calculate the work done by the boy.

A boy ''A'' of mass 50kg climbs up a stair case in 10s. Another boy ''B'' of mass 60kg climbs up a same staircase in 15s. The ratio of their power developed by the boys ''A'' and ''B'' is