John throws a ball just that it reaches the top of 10 meter

John throws a ball just that it reaches the top of 10 meter high flagpole. How long the ball in the air before it came back to his hand?

Solution

From

S= V_ot+(1/2)at²

10=0+(1/2)*9.8*t²

t=1.43 seconds

total time taken to comeback to hand is

T=1.43+1.43=2.86 seconds