Question

Suppose the position of an object moving in a straightline is given by `s(t)= t^3 -2t^2 +5`. What is the instantaneous velocity when t = 2?

Answer 1

`v(2)=4ms^(-1)`

Explanation:

the velocity of an object `v(t)` is given by`(ds(t))/(dt)`

`s(t)=(t^3-2t^2+5) m`

`v(t)=(ds(t))/(dt)=3t^2-4t`

the required instantaneous velocity will be at `t=2`

`v(2)=[(ds(t))/(dt)]_(t=2)=3xx2^2-4xx2=4ms^(-1)`