Applications Of Derivatives Question 163

Question: The equation of motion of a particle is given by $ s=2t^{3}-9t^{2}+12t+1 $ ,where s and t are measured in cm and sec. The time when the particle stops momentarily is

Options:

A) 1 sec

B) 2 sec

C) 1, 2 sec

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

$ \frac{ds}{dt}=6t^{2}-18t+12 $ = velocity = 0 (when particle stopped)

therefore $ 6t^{2}-18t+12=0\Rightarrow (t-1),(t-2)=0 $

Hence time 1, 2 sec.