What is the maximum frictional force in the knee joint of a person who supports 66.0 kg of her mass on that knee? (b) during strenuous exercise it is possible to exert forces to the joints that are easily ten times greater than the weight being supported. what is the maximum force of friction under such conditions? the frictional forces in joints are relatively small in all circumstances except when the joints deteriorate, such as from injury or arthritis. increased frictional forces can cause further damage and pain

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)