Thermodynamics question (temp change, entropy, energy)...?

I got through just about all of the problems with the exception of this last one.





A water parcel of mass m and initial temperature 15 C falls over a waterfall that is 100m high. Calculate the change in temperature, change in specific entropy, and amount of energy per unit mass degraded during the fall.





I can calculate the change in entropy using the standard s = -dQ/dT relationship once I find the change in temperature. Where I'm actually stuck is figuring out how to calculate the change in temp. and the amount of energy degraded. Would I use the first law?





Any help would be greatly appreciated!

Thermodynamics question (temp change, entropy, energy)...?
Just assume the energy gained is the potential gravitational energy U=mgh, with h=100 meters, and then the heat capacity of water, etc.