A microwave is turned on for 150 seconds and it uses 9000 J of energy. The total power needed is 125 W. Calculate the efficiency of
the microwave oven

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.

I’ve been stuck on this for a while

Hunter’s velocity was 4.5 m/s. at the end of his race, his velocity was the same. which best describes his movement? his movement stopped. his acceleration is zero. his time was constant. his acceleration was positive.