Question

A car start from rest and acquire a velocity of $54\text{km/h}$ in $2\text{sec}$. Find the acceleration of the car.

• A. $5{\text{m/s}}^2$
• B. $7.5{\text{m/s}}^2$
• C. $15{\text{m/s}}^2$
• D. $7{\text{m/s}}^2$

Answer 1

The correct option is B $7.5{\text{m/s}}^2$

As car starts from rest, si its initial velocity, say, $v_i=0$
Acceleration of the car is given by
$a=\frac{\Delta v}{\Delta t}$
Final velocity of car, $v_f=54\text{km/h}=\frac{54\times 1000}{3600}=15\text{m/s}$
Hence, $a=\frac{15-0}{2}=7.5{\text{m/s}}^2$