A particle moves along a line so that its distance from a fixed point after $t$ seconds is $s = t^{3} - 6t^{2} + 9t$ metres. At which times is it momentarily at rest?

t = 1

s and

t = 3

sCorrect answerYour answer

t = 0

s and

t = 3

sCorrect answerYour answer

t = 2

s onlyCorrect answerYour answer

t = 3

s onlyCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer A

Correct answer: A

Worth noting

$t = 0$ and $t = 3$ are when $s = 0$ , the particle at the fixed point, not at rest.

Ten questions from Chain Rule, Log Differentiation & Rate of Change, at your own pace.

Ten questions from Chain Rule, Log Differentiation & Rate of Change, at your own pace.

A particle moves along a line so that its distance from a fixed point after ttt seconds is s=t3−6t2+9ts = t^{3} - 6t^{2} + 9ts=t3−6t2+9t metres. At which times is it momentarily at rest?