Applications Of Derivatives Question 220

Question: The distance travelled s (in metre) by a particle in t seconds is given by, $ s=t^{3}+2t^{2}+t. $ The speed of the particle after 1 second will be

[UPSEAT 2003]

Options:

A) 8 cm/sec

B) 6 cm/sec

C) 2 cm/sec

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

$ s=t^{3}+2t^{2}+t $

$ v=\frac{ds}{dt}=3t^{2}+4t+1 $
Speed of the particle after 1 second
$ {v_{(t=1)}}={{( \frac{ds}{dt} )}_{(t=1)}}=3\times 1^{2}+4\times 1+1=8,cm/sec. $