The displacement s of a moving particle at a time t is given by `s=5+20t-2t^(2)`. Find its acceleration when the velocity is zero.

The displacement s of a moving particle at a time t is given by `s=5+2

1.	The displacement s of a moving particle at a time t is given by `s=5+20t-2t^(2)`. Find its acceleration when the velocity is zero.
Answer» Given, `s=5+20t-2t^(2)` velocity `(v) =(ds)/(dt)=20-4t` Now, `v=0.` `therefore 20-4t=0` `therefore t=5` and acceleration `(a) =(dv)/(dt)=-4` `((dv)/(dt))_(t=5)=-4` Hence, the acceleration is-4 unit/`sec^(2).`