Question

A car starts from rest and moves along a straight line with an acceleration of
$6ms–2$. The displacement of the car in the fourth second is _________ m.

• A. $48$
• B. $21$
• C. $0$
• D. $20$

Answer 1

The correct option is A

$48$

Step 1: Given data.

let

s= distance,

u= initial velocity

a=acceleration

t=time

As a car starts moving from rest, $u=0$

Given, $a=6m{s}^{-2}$ and $t=4sec$

Step 2 Calculation of answer

Therefore, the equation of motion.

$s=u+\frac{1}{2}a{t}^2$

$$\begin{gathered} s=0\hspace{0.17em}+\frac{1}{2}\times 6\times 4\times 4 \\ s=48\mathrm{m} \end{gathered}$$

Hence, Option A is correct.