Name at least six forms of energy.

Two children $A$ and $B$ each weighing $20 \, kg$ climb a rope up to a height of $10 \, m$. Child $A$ takes $10 \, s$ and child $B$ takes $20 \, s$ to climb. State whether the work done by both is equal or unequal. Who has more power?

$(i)$ $A$ 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? $(g = 10\, m s^{-2})$

$(a)$ An arrow moves forward when released from a stretched bow. Explain the transformation of energy in the process.
$(b)$ $A$ boy of mass $50 \, kg$ climbs up a vertical height of $100 \, m$. Calculate the amount of potential energy he gains.

$(a)$ The Earth,moving around the Sun in a circular orbit,is acted upon by a force,and hence work must be done on the Earth by the force. State whether the statement is correct or not. Give reasons for your answer.
$(b)$ $A$ coolie holding a heavy box is waiting at the bus stand for $15$ minutes. How much work is done by him?
$(c)$ $A$ man weighing $70 \, kg$ carries a weight of $10 \, kg$ to the top of a tower $100 \, m$ high. Calculate the work done by the man. $(g = 10 \, m s^{-2})$

Define work,energy,and power. Give the $SI$ units for each of these quantities. $A$ man whose mass is $80 \, kg$ climbs up $30$ steps of the stairs in $30 \, s$. If each step is $12.5 \, cm$ in height,calculate the power used in climbing the stairs. $(g = 10 \, m \, s^{-2})$