Write the formula for potential energy (blank 1). Calculate the potential energy in Joules (1) of an object weighing 4 kilograms and
sitting 4 meters off the ground if gravity is 9.8 meters per second squared. Enter your
answer (blank 2)

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.