Force of Gravity:
It is a particular case of motion, under a constant acceleration of (g) where its value is taken as 9.8 m/s2. If there is a free fall under gravity, the expression for velocity and distance traveled in terms of initial velocity, time and gravity acceleration will b:
v = ut + gt
s = ut + (1/2)gt22 = u2 + 2gs
But, if the motion takes place against the force of gravity, the particle is projected upwards, the corresponding equations will be:
v = – u + gt
s = -ut + (1/2)gt22 = -u2 + 2gs