Physics

# Describe Equations of Motion

We can solve the problems regarding motion of any moving bodies by using only four equations. These equations are called equation of motion. These equation are applicable when the object moves along straight line with uniform acceleration. Let a body with initial velocity u move with uniform acceleration a. Let the final velocity be v after traveling a distance s at time t.

Let the initial velocity of a body be u moving with uniform acceleration a. After traveling a distance s in time t its final velocity becomes v. We express the equations of motion by the following symbols. These symbols are:

u = initial velocity

a = uniform acceleration

t = traveled time

s= displacement i.e. distance traveled in time t

v = final velocity i.e. velocity after time t

There are five quantities “Suvat” are related in such a way that if we know the value of three, we can find the value of other two. So there are four equations and every equations has four quantities we can find the value of unknown quantities using the values known quantities by this equation.

We know, Acceleration, a = (v – u) / t

So, v = u + at …. …. ….(1)

We also find there

average speed = (distance traveled/time)

or, (u+v)/2 = s/t

so, s = (u+v)t / 2  ….. ….. …..(2)

Calculate: Put the value of v of eq (1) into equation (2)

S = ut + ½ at2 …. …….. ……..(3)

Calculate: Find the value of t from equation (1) and put it in eqn (2) and by cross multiplication arrange the terms.

v2 = u2 + 2as

If it is said in a problem the body starts its motion from rest, the initial velocity will be u = 0