1. The problem statement, all variables and given/known data Consider a rock having a mass of 5 kg and a bucket containing 50 kg of liquid water. Initially, the stone is 20 m above the water, and the stone and the water are at the same temperature, T1 (state 1). The stone then falls into the water. For the system stone + water, determine ΔU, ΔKE, ΔPE, Q and W for the following changes of state: 1 to 2, 2 to 3, and 3 to 4, with: (a) State 2: the stone is just about the enter the water; (b) State 3: the stone has just come to rest in the bucket; (c) State 4: heat has been transferred to the surroundings in such an amount that the stone and water are at the same temperature T1 (temperature of state 1). 2. Relevant equations ΔE = Q - W (First Law) ΔE = ΔE(mechanical) + ΔU ΔE(mechanical) = ΔKE (kinetic energy) + ΔPE (potential energy) 3. The attempt at a solution I think I am messing up when establishing my system... For example, when trying to calculate the kinetic energy of the system, it should be zero since the entire rock + water are one system and the entire system is not moving. However, the rock has kinetic energy from state 1 to state 2, so should I take that into account? Same with potential energy. I also have no idea how to calculate Q and W other than using ΔE = Q - W. Is there another way? Tips are appreciated!