Question

Define power. How will you differentiate between kW and kW h? If the velocity of a ball is tripled, what will be the ratio of

Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it.

A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g =10 m s⁻²)

The power of a motor pump is 2 kW. How much water per minute the pump can raise to a height of 10 m? (Given g = 10 m s⁻²)

Is it possible that an object is in the state of accelerated motion due to external force acting on it, but no work is being done by the force. Explain it with an example.