Answer:
Explanation:
Given
Object is thrown with a velocity of 
Acceleration due to gravity is -g (i.e. acting downward)
Vertical distance traveled by object is given by
where v=final velocity
u=initial velocity
a=acceleration
s=displacement
at maximum height final velocity is zero


time taken to reach maximum height
using
v=u+at
0=9-gt

Answer:
Aerobic exercise became part of this movement in the 1970s.