Question

A particle is moving in a straight line according to as S = 24t + 3t² - t³, then the time it will come to rest is ______ 

Options

• -18 sec

• 10 sec

• 4 sec

• -4 sec

Answer 1

A particle is moving in a straight line according to as S = 24t + 3t² - t³, then the time it will come to rest is 4 sec.

Explanation:

`(dS)/dt` = velocity = 24 + 6t - 3t²

When particle comes to rest, v = 0

⇒ 3t² - 6t - 24 = 0

⇒ t = 4 sec