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 boy is moving on a straight road against a frictional force of 5 N. After travelling a distance of 1.5 km he forgot the correct path at a round about (Fig. 11.1) of radius 100 m. However, he moves on the circular path for one and half cycle and then he moves forward upto 2.0 km. Calculate the work done by him.

The velocity of a body moving in a straight line is increased by applying a constant force F, for some distance in the direction of the motion. Prove that the increase in the kinetic energy of the body is equal to the work done by the force on the body.