Imagine you are on the top of a mountain with four basketballs. The mass of the four basketballs are 100 kilograms, 200 kilograms, 300 kilograms, and 400 kilograms. If the basketballs rolled down the hill, which one would supply the greatest force at the bottom of the mountain (assume that their velocities were equal at the bottom of the mountain)?

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)