Question

The displacement 's' of a moving particle at time 't' is given by s = 5 + 20t — 2t². Find its acceleration when the velocity is zero.

Answer 1

`s=5+20t-2t^2`

`v=(ds)/dt =20-4t`

`v=0`

`20-4t=0`

`4t=20`

`t=5`

`a=(dv)/dt=-4 , "which is contatnt"`

Hence, acceleration is -4 when velocity is zero.