Aballplayer catches a ball 3.0s after throwing it vertically upward. with what speed did he throw it, and what height did it reach?

We can find final velocity using the equation as follows:  

vf = vi + g*t 

Substituting our known values for vi and g we obtain: 

vf = vi + g*t 
vf = 0 + (9.8)*(1.5) [ 1.5 s since it is the time it take to reach the top and to fall back)

vf = 14.7 = 15m/s

We can find the distance traveled using 

d = vi*t + 1/2g*t^2 

Substituting our values for vi, g and t we get 

d = 0*(1.5) + (1/2)*(9.8)*(1.5)^2 

d = 11m

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