A stone is thrown vertically upwards from the top of a tower `64m` high according to the law of motion given by `s=48t-16t^(2)`. The greatest height attained by the stone above ground is

Options

A. `36m`
B. `32m`
C. `100m`
D. `64m`

Answer

C

Explanation

Given `s=48t-16t^(2)`…………….i
`implies(ds)/(dt)=48-32t`
At the greatest height `v=(ds)/(dt)=0`
`implies 48-32t=0impliest=3/2`
then from eq. i `s=48xx3/2-16(3/2)^(2)=36m`
`:.` Total height `=64+36=100m`