Work and Energy...

How much energy in kilowatt hour is consumed in operating ten 50 watt bulbs for 10 hours per day in a month (30 days)

The hydroelectric plants do not produce electricity, if the water level in the dam is less than 34 m.

A machine raises a load of $$750N$$ through a height of $$16m$$ in $$5s$$. Calculate work done by machine:

A body when acted upon by a force of $$10\ kgf$$, gets displaced by $$0.5\ m$$. Calculate the work done by the force, when the displacement is in the direction of force.

A boy carrying a box on his head is walking on a level road from one place to another. The work done by him against the gravitational force is zero. This statement is :

Name the type of energy (kinetic energy $$K$$ or potential energy $$U$$) possessed in the following case.

A man raises a box of mass $$50 \ kg$$ to a height of $$2 \ m$$ in $$2 \ minutes$$, while another man raises the same box to the same height in $$5 \ minutes$$. What is the ratio of work done by them ?

Before a rubber ball bounces off from the floor, the ball is in contact with the floor for a fraction of second. Which of the following statements are correct?