A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 15m/s when the hand is 2.0m above the ground.
How long is the ball in the air before it hits the ground? (The student moves her hand out of the way.) Express your answer using two significant figures.
s= (v^2- u^2)/2a
s= -225/-19.6= 11.47 m
total s= 13.47 m
s= ut +1/2 at^2
t=1.66 sec time taken during fall
time taken going up= t1
total time taken= t+t1= 3.19 secs