Question

A car moves along a straight line whose motion is given by $S=12t+3t^2+2t^3$, where $S$ is in meters and $t$ is in seconds. The initial velocity of the car will be

• A. $7m/s$
• B. $9m/s$
• C. $12m/s$
• D. $16m/s$

Answer 1

Answer: (C)

$12m/s$

Velocity is defined as $\left(\frac{ds}{dt}\right)$
$\Rightarrow \overrightarrow{V}=\frac{ds}{dt}=\frac{d}{dt}(12t+3t^2+2t^3)=12+6t+6t^2$

At $t=0,v=12m/s$