The displacement of a particle is metres

MATHEMATICS · Single correct · CBSE · Mathematics · Applications of Derivatives · Applications of Derivatives

Problem

The displacement of a particle is

s(t)=t^{3}-6t^{2}+9t

metres. Which of the following statements is correct? (a) Velocity becomes zero at

t=1\,\text{s}

and

t=2\,\text{s}

; acceleration is negative at

t=1\,\text{s}

. (b) Velocity becomes zero at

t=1\,\text{s}

and

t=3\,\text{s}

; acceleration is negative at

t=1\,\text{s}

. (c) Velocity becomes zero at

t=1\,\text{s}

and

t=3\,\text{s}

; acceleration is positive at

t=1\,\text{s}

. (d) Velocity becomes zero at

t=1\,\text{s}

and

t=3\,\text{s}

; acceleration is zero at

t=1\,\text{s}