Name at least six forms of energy.

Calculate the power of an electric motor that can lift $800 \, kg$ of water to store in a tank at a height of $1500 \, cm$ in $20 \, s$. $(g = 10 \, m s^{-2})$ (in $, kW$)

Which would have a greater effect on the kinetic energy of an object: doubling the mass,or doubling the velocity?

State whether the following statement is true or false:
The unit of work is watt.

$(i)$ $A$ light and a heavy object have the same momentum. What is the ratio of their kinetic energies? Which one has a larger kinetic energy?
$(ii)$ $A$ ball is dropped from a height of $10\, m$. If the energy of the ball reduces by $40\%$ after striking the ground,how high can the ball bounce back? $(g = 10\, m s^{-2})$

When a stone of mass $m$ falls through a vertical height $d$,the decrease in the gravitational potential energy is: