2) Derivation for the Equation of Motion s = ut+at2
Velocity is defined as the rate of change of displacement. This is mathematically represented as:
\(
Velocity = \frac{{Displacement}}
{{Time}}
\)
Rearranging, we get
Displacement = Velocity x Time
If the velocity is not constant then in the above equation we can use average
velocity in the place of velocity and rewrite the equation as follows:
\(
Displacement = \frac{{Initial Velocity + Final Velocity}}
{2}x\,Time
\)
\(
s = \frac{{v + u}}
{2}\,x\,t
\)
From the first equation of motion, we know that v = u + at. Putting this value of v
in the above equation, we get
\(
s = \frac{{v + (u + at)}}
{2}\,x\,t
\)
\(
s = \frac{{2u + at}}
{2}\,x\,t
\)
\(
s = \left( {\frac{{2U}}
{2} + \,\frac{{at}}
{2}} \right)\,x\,t
\)
\(
s = \left( {u + \,\frac{{at}}
{2}} \right)x\,t
\)
On further simplification, the equation becomes: s = ut+at2......(ii)