A man throws ball with the same speed vertically upwards one after the other at an interval of 2 seconds. What should be the speed of the throw so that more than two balls are in the sky at any time ? (Given g=9.8m/s2)
A. More than 19.6m/s
B. At least 9.8m/s
C. Any speed less than 19.6m/s
D. Only with speed 19.6m/s
