A ball is thrown vertically upwards with an initial velocity of `5 m//sec` from point `P` as shown `Q` is a point `10 m` vertically below the point `P`. Then the speed of ball at point `Q` will be : (take `g=10 m//s^(2)` and neglect air resistance)

Options

A. `7.5 m//sec`
B. `10 m//sec`
C. `15 m//sec`
D. `17.5 m//sec`

Answer

C

Explanation

`v2 =u2 +2 as`
`v2 =(5)_(2) +2 xx 10 xx 10`
`v2 =25 +200 rArr 225`
`v =15 m//sec`.