In a lab investigation, one group of students (group A) measures the speed of a 0.1kg car at 2.5m/s at the bottom of a hill. Another group of students (group B) measures the speed of the car at 3m/s at the bottom of the hill. Both cars started at the top of a hill that is 1m high. Calculate the potential and kinetic energies for each group's car.

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.