Question

A bus moving along a straight line at 20 m/s undergoes an acceleration of 4$m/s^2$. After 2 seconds, its speed will be :

(a) 8 m/s

(b) 12 m/s

(c) 16 m/s

(d) 28 m/s

Answer 1

Step 1: Given data:

The initial velocity of the bus($u$) = $20m{s}^{-1}$

Acceleration in the bus($a$) = $4m{s}^{-2}$

Time($t$) = $2sec$

Step 2: Calculation of the speed of the bus after 2sec:

The first equation of motion, $v=u+at$

Where $u$ = Initial velocity, $v$ = Final velocity, $a$ = acceleration and $t$ = time

Putting the values we get;

$v=20m{s}^{-1}+4m{s}^{-2}\times 2s$

$v=20+8$

$v=28m{s}^{-1}$

Thus,

Option d) $28m{s}^{-1}$ is the correct option.