Aball is thrown vertically upward, which is the positive direction. a little later it returns to its point of release. the ball is in the air for a total time of 8.0 s. what is its initial velocity? neglect air resistance

u=78.4m/s

Explanation:

A ball is thrown vertically upward, which is the positive direction.A little later it returns to its point of release.The ball is in the air for a total time of 8.0 s.What is its initial velocity? Neglect air resistance

from newtons equation of motion

s=ut

v=u+at

v=0 because at maximum height reached by the ball the ball stops moving

0=u-9.8*8

u=78.4m/s

u=initial velocity

v=final velocity

a=acceleration due to gravity, 9.81m/s^2

t=time it takes in air

s= distance to get to the maximum before returning

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.

the area between the graph and the t axis