A boy climbs on to a wall that is 3.4 m high and gains 2250 J of potential energy. What is the mass of the boy? Take g = 9.8 m/Sec2
70 kg
50 kg
62.5 kg
67.5 kg
A balloon with a rope ladder hanging from it has a mass 4m. With a boy of mass m at the lowest rung of the ladder, the balloon is floating in equilibrium in the sky. The boy climbs the ladder of length L reaching its top. If g is acceleration due to gravity, then the gain in the gravitational potential energy of the boy is