Question

The velocity acquired by a body moving with uniform acceleration is $30m{s}^{-1}$ in 2 seconds and $60m{s}^{-1}$ in 4 seconds. The initial velocity is :-

• A. zero
• B. $2m{s}^{-1}$
• C. $4m{s}^{-1}$
• D. $10m{s}^{-1}$

Answer 1

The correct option is A zero

According to question

at $t=2s$ , $v=30m/s$

at $t=4s$ , $v=60m/s$

So,

acceleration = $\frac{dv}{dt}=\frac{60-30}{4-2}=15m/s^2$

$a=15m/s^2$

from $1^{st}$ equation of motin is first case

$v=u+at$

$30=u+15\left(2\right)$
$u=0m/s$

Hence (A) option is correct answer