Find the velocity of a body of mass $100 \, g$ having a kinetic energy of $20 \, J$. (in $, m s^{-1}$)

Define potential energy. Write an expression for potential energy. Write the $SI$ unit of potential energy.

$(a)$ Define potential energy. Write an expression for potential energy of an object of mass $m$ raised through a height $h$.
$(b)$ Find the energy possessed by an object of mass $10 \, kg$ when it is raised to a height of $6 \, m$ above the ground. (Given $g = 9.8 \, m s^{-2}$)

$A$ ball is dropped from a height of $10\, m$. If the energy of the ball reduces by $40\%$ after striking the ground,how much high can the ball bounce back (in $,m$)? $(g = 10\, m \,s^{-2})$

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

$A$ light and a heavy object have the same momentum. Find the ratio of their kinetic energies. Which one has a larger kinetic energy?