@ Alchemy- To answer this, you need to use the following equation PE=mg[delta]h. You will also need to convert the grams into kilograms, and the number of feet into meters. Two hundred and eighty-seven grams is 0.287 kilograms. The change in height is 34 feet, which is the equivalent of 10.363 meters. Now just plug in your variables and solve the equation.
[delta]PE=0.287kg*9.80m/s^2*10.363m=29.15J. Your change in energy is 29.15 Joules.