Physics

Mathematical Example on Velocity

Question 1: Velocity of a car increases uniformly at the rate of 5 ms-1 and after 10 s becomes 45 ms-1 . Find the acceleration of the car.

Solution

Here,

initial velociti u = 5ms-1

final velociti v = 45ms-1

time t = 5s

acceleration a = ?

We know,

a = (v – u)/t

or, a = (45 ms-1 -5 ms-1)/5s

= 40 ms-1 / 5s  = 8 ms-2

Ans : 8 ms-2

 

Question 2: The Velocity of a car decreases uniformly from 20 ms-1 and after 4s it becomes 4 ms-1. Find the acceleration of the car.

Solution

Here,

initial velocity u = 20 ms-1

final velocity v = 4 ms-1

time t = 4 s

acceleration a = ?

We know,

a = (v – u)/t

or, a = (4 ms-1 – 20 ms-1)/4 s

= – 16 ms-1 / 4 s  = – 4 ms-2

Ans : – 4 ms-2