Question

A car is stopped at a traffic light. It then travels along a straight road such

that its distance from the light is given by:

𝑥(𝑡) = 2.4𝑡

2 − 0.120𝑡

3

Answer 1

$x=2.4t^2-0.120t+3$

Differentiate with respect to time

$v=\frac{dx}{dt}$

$v=\frac{d(2.4t^2-.120t+3)}{dt}=4.8t-0.120$

$v=0$

$4.8t-0.120=0$

$t=\frac{0.120}{4.8}=0.025sec$