How High and How Long Does a Volleyball Go When Hit Upwards?

[inedhelpinphy]

Homework Statement

Stephanie hits a volleyball from a height of 0.8m and gives it an initial velocity of 7.5m/s straight up.?
a. how high will the volleyball go?
b. how long will it take the ball to reach its maximum height? (hint:@ max height, v= 0m/s)

Homework Equations

im not sure but maybe d=vit+1/2 at^2

The Attempt at a Solution

tried a lot of things :/

 

[Delphi51]

d=vit+1/2 at^2 is good, but you also need v = vi + a*t so you can take advantage of that hint about the v being zero at maximum height.

 

[rl.bhat]

Show your attempts.

 

[inedhelpinphy]

tyvm! i think you use vf=vi+at to find how high it will go ?

 

[inedhelpinphy]

Show your attempts.

i did vf^2= 7.5^2+2(-9.81)(.8)
im not sure if its how you do this