Projectile ---- spring ------ table

[aronno]

im going to do a extended practical report soon and i need some help getting the aims?

THE PRAC; a spring is set on top of a table H meters high. and is lauched horizotally from edge of table and the projectile is veiwed as if falls.

AIM:
i only have the relationship b/w:
1- elastic potential enery and how it affects the initial velocity hence the R: range!
2- intial velocity and its flight times (should be the same)

Is there anything else i can analyse and measure to confirm a theretical understanding....
thanks all!!!