Katie blows up a balloon and ties it so there is a fixed amount of air in the balloon. She wraps a piece of string around the widest part of the balloon, and measures it to find the size of the balloon. She has access to: A freezer  A warm cupboard A cold refrigerator A normal temperature classroom. Write a plan to collect results to answer the question: How does the temperature affect the size of a blown up balloon?

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)