If an electric bulb of power 1000 W is kept switched on for exactly 1 hour, what will be the total electrical energy consumed?

A ball of mass 3 kg is placed on a shelf 2 m above the ground. The gravitational potential energy of the ball is (take g = 10 m/s2):

A person trying to lose weight lifts a 100 kg mass up to a height of 0.5 meter, 1000 times. Assuming g = 9.8 m/s2 and that the potential energy lost each time the mass is lowered is completely dissipated, what is the total work done against the gravitational force?