Question

A car moves along a straight line whose equation of motion is given by $s=24t+3t^4–2t^3$, where $s$ is in metre and $t$ is in second. The velocity of the car at $t=0$ will be

• A. $7\text{m/s}$
• B. $9\text{m/s}$
• C. $12\text{m/s}$
• D. $24\text{m/s}$

Answer 1

The correct option is D $24\text{m/s}$

Given $s=24t+3t^4–2t^3$

From definition of instantaneous velocity,

$v=\frac{ds}{dt}=24+12t^3-6t^2$

at $t=0\Rightarrow v=24\text{m/s}$