Equation of Motion for a Body Moving Under Gravity

Show that the time taken by the two objects of different masses to fall through a certain height is equal. 

Why is it easier to stop a tennis ball than a cricket ball moving with the same speed?

A ball thrown up vertically returns to the thrower after $6 \mathrm{s}$, ($\mathrm{g}=10 \mathrm{m}/{\mathrm{s}}^2$)
Find
(a) the velocity with which it was thrown up
(b) the maximum height it reaches
(c) its position after $4 \mathrm{s}$.

A ball is thrown vertically upwards, prove that its time of ascent is equal to time of descent.

Write the equations of motions for a body thrown vertically upwards.

Write the equations of motion for freely falling body.