# Derive equations of motion?

First equation of motion:

Consider a body having initial velocity u,If it is subjected to an acceleration 'a' so that after time 't' its velocity becomes v.

By the definition of acceleration

acceleration=Change in velocity/time taken

a=(v-u)/t

v=u+at

Second equation of motion:

Suppose the distance travelled by the above body in time t=s

we have average velocity=(Initial velocity+Final velocity)/2 Third equation of motion: • 414

HI

## Third Equation of Motion

Let 'u ' be the initial velocity of an object and a be the acceleration produced in the body. The distance travelled 'S ' in time 't ' is given by the area enclosed by the v - t graph.

##### Graphical Derivation of Third Equation

S = area of the trapezium OABD.     Substituting the value of t in equation (1) we get,

##### 2aS = (v + u) (v - u)

(v + u)(v - u) = 2aS [using the identity a 2 - b 2 = (a+b) (a-b)]

v 2 - u 2 = 2aS III Equation of Motion

hope it helps u....

• 153
What are you looking for?