Question

A body has an initial velocity of $4m{s}^{-1}$ and deceleration of $4m{s}^{-2}$, then what is its final velocity after travelling 2 m?

• A. $4m{s}^{-1}$
• B. $0m{s}^{-1}$
• C. $5m{s}^{-1}$
• D. $2m{s}^{-1}$

Answer 1

The correct option is B

$0m{s}^{-1}$

Given, initial velocity $u=4m{s}^{-1}$ and distance covered, s = 2 m.
Since the body is decelerating, $a=-4m{s}^{-2}$
Let the final velocity be 'v'.
From the third equation of motion, we know, $v^2-u^2=2as$
$v^2=4^2+(2\times -4\times 2)$ = 0
$\therefore$ Final velocity of the body is zero.