A man throws balls with the same speed vertically upwards one after the other at an interval of 2s. What should be the speed of the throw so that more than two balls are in the sky at any time ? (Given `g = 9.8 m//s^(2)`)

Options

A. More than 19.6 m/s.
B. At least 9.8 m/s.
C. Any speed less than 19.6 m/s
D. Only with speed 19.6 m/s.

Answer

A

Explanation

Time of flight for ball must be more than 4 sec.
`Tgt4 secrArr(2u)/(g)gt4rArr(u)/(g)gt2rArrugt2g`
`rArrugt2xx9.8rArrugt19.6m//s`