Question

The acceleration of the particle moving in positive $x-$ direction with an initial velocity of $20\text{m/s}$ is $4{\text{m/s}}^2$. Its velocity at $t=5\text{sec}$ is

• A. $22\text{m/s}$
• B. $40\text{m/s}$
• C. $30\text{m/s}$
• D. $25\text{m/s}$

Answer 1

The correct option is B $40\text{m/s}$

Given, $a=4{\text{m/s}}^2,u=20\text{m/s}\text{and}t=5\text{sec}$
Using first equation of motion we have
$v=u+at$
$\Rightarrow v=20+4\times 5=40\text{m/s}$
Hence, velocity at $t=5\text{sec}$ is $40\text{m/s}$.