How Do You Calculate the Initial Velocity of a Juggling Ball?

[c.kal]

You are practicing your juggling skills by throwing a single juggling ball back and forth between level hands. The distance between your hands is 40 cm. Between catches, the ball is in the air 0.85 s. Calculate the magnitude and direction of initial velocity of the juggling ball each time you throw it.

i'm not sure where to start on this one..

 

[NascentOxygen]

Hi c.kal, I see you are new here. http://imageshack.com/a/img515/4884/welcomesign.gif

You start this problem the same way as you start any physics problem---you write down what you are given and what you are required to find. This includes a sketch because things are clearer if you have some pictorial aid to focus on. Then you write down as many relevant equations as you can. Next, cross out those equations that you can see are of no use here.

Then, you get serious ...

 

[c.kal]

I sketched and labeled it but I still can't figure out where to start

 

[NascentOxygen]

Post what you've done here. Show the kinematics equations that might be useful.

Hint: when a ball thrown into the air returns to the level it was thrown from, its displacement at that point equals zero.