A man throws balls 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 air at any time (Given g=9.8m/s2 )
Interval of ball throw 2 sec
If we want that minimum three (more than two) ball remain in air then
time of flight of first ball be greater than 4 sec.
T> 4 sec
2ug>4 sec⇒ u> 19.6 m/s
for u=19.6. First ball will just strike the ground
second ball will be at highest point
Third ball will be at point of projection or at ground