Alex performs a lab experiment with a radio-
controlled cart. He measures the speed of the
cart as it accelerates along a straight track. The
following table shows his data.
Time (s) Speed (m/s)
0 0
1 1
2 1.9
3 3
What is the average acceleration of the cart after
3 s?

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)