Question

A body with an initial velocity of $18km{h}^{-1}$ accelerates uniformly at the rate of $9cm{s}^{-2}$ over a distance of 200 m. Calculate its final velocity in $m{s}^{-1}$.

• A. 0
• B. 7.81
• C. 15.6
• D. 3.9

Answer 1

Answer: (B)

7.81

Given, initial velocity $u=18km{h}^{-1}$
$=\frac{18000m}{60\times 60}=5m{s}^{-1}$

Acceleration $a=0.09m{s}^{-2}$
and distance s = 200 m
From equation of motion $v^2=u^2+2as$,
We get, $v=\sqrt{5^2+2\times 0.09\times 200}m/s=7.81m/s$