Question

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

• A. $Zero$
• B. $2m/s$
• C. $4m/s$
• D. $10m/s$

Answer 1

Answer: (A)

$Zero$

Let,

Constant acceleration, $a$

Initial velocity $u$

Apply kinematic Equation

$v=u+at$

$a=\frac{v-u}{t}$

Compare acceleration at both event at time, $t_1\&t_2$

$\frac{v_2-u}{t_1}=\frac{v_3-u}{t_2}$

$\Rightarrow \frac{30-u}{2}=\frac{60-u}{4}$

$\Rightarrow u=0$

Initial velocity $u=zero$