1. Okay. So, my lab is to bounce a ball at a given high while i calculate the time, mass, and different heights. Given these I find the PE, Velocity, and Difference in PE. I've gotten most of the lab complete but there is a final question that asks "If you wanted the golf ball to rebound to a height of 3ft, which was the tested initial height, how high in units of ft would the golf ball need to be initially placed before released. 2. There is also a question that asks: "Calculate the difference in PE in J between the initial height and rebound height, and explain what happened to account for the loss of height in terms of conservation of energy?" I understand how to find the difference the PE from the initial height and the PE after it was rebounded but what does she mean by the conservation of energy thing? 3. For the golf ball I have an initial height of .91m, a PE of .4 J, a velocity of 2.33 m/s, avg rebound height of .56m w/ a PE of .25 J, and the difference is .15 J. 4. Im not sure where to start, really. I thought of possibly doing .4J/.25J and plugging that into PE=mgH but I'm not sure if that'd give me the answer. If anyone could please help me that'd be great. This paper is due at 8am tomorrow morning. Thanks! Additional info: M=45g Initial height 1 yd travel time: .39sec.