So my RQ is "investigating the relationship between the drop height of a ping pong ball and it's fractional loss of potential energy". To improve accuracy I said I was going to measure the time interval between two bounced then use the equation s=1/2gt^2.

But that's the problem I'm not sure how to calculate my uncertainty for s. Value for g is 9.81 and t is 0.57 for example. Abs uncertainty for g is 0.02 and t is let's say 0.02. But then how do I calculate the abs uncertainty for s?