physics question need help?

Question

please help with my homework. need kind explaination.
A person threw a ball vertically up. 3.0 seconds later it hit the ground. What is initial speed when he threw the ball and what is total distance. I need the formular also please. thank you

Answer 1

In this problem
y(t)=v0*t-.5*g*t^2
you are given t when y(t) is equal to zero (the second time, the first time is t=0)

0=v0*3-.5*3*10*9

solve for v0

Once you have v0, the apogee is calculated by first finding t when v(t) is zero
or
0=v0-g*t
t=v0/g

plug that into y(t) to find the max height
y(v0/g)=.5*v0^2/g

multiply it by 2 for total distance
v0^2/g

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