An engineering student was helping in the design of a new runway. His mentor told him the airplanes must reach a ground velocity of 55 m/s before they can take off. These planes are
capable of being accelerated at a rate of 2.8 m/s?.
a. How long will it take the planes to reach takeoff speed?
b. What must be the minimum length of the runway?

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.