Question

The magnitude of deceleration required for a body, moving at a speed of $10 m/s$ to come to a complete halt at a distance of $100\, m$ is

• A. 20 $m/s^2$
• B. 10 $m/s^2$
• C. 2 $m/s^2$
• D. 0.5 $m/s^2$
• E. 1 $m/s^2$

Answer 1

Answer: (D)

Given speed of body $(u)=10\,m / s$
and distance travelled $(s)=+100\,m$
From the equation of motion
$v^{2}-u^{2} =2 a s$
Given, $ v=0, a =?$
$-(10)^{2} =2 a(100 \,m ) $
$\Rightarrow a =-\frac{100}{2 \times 100}$
$=-0.5 \,m / s ^{2}$
So acceleration is negative with magnitude of $0.5\,m / s ^{2}$