The space s described in time t by a particle moving in a straight line is given by s = t5 – 40t3 + 30t2 + 80t – 250 Find the minimum value of acceleration.
Given:
The Distance(S) covered by a particle in time t is given by
⇒ S = t5 - 40t3 + 30t2 + 80t - 250
We know that acceleration of a particle is given by .
⇒
⇒
⇒
⇒
We need acceleration to be minimum,
We know that for maxima and minima,
⇒
⇒
⇒
⇒ t2 = 4
⇒ t = 2 (∵ Time cannot be negative)
Differentiating ‘a’ again,
⇒
⇒
At t = 2
⇒
⇒ >0(Minima)
We get minimum for t = 2 sec,
The corresponding acceleration at t = 2 sec is,
⇒ a = 20(2)3 - 240(2) + 60
⇒ a = 160 - 480 + 60
⇒ a = - 260
∴ The minimum acceleration is - 260.