PLEASE HELP A 64.0-kg male ice skater is facing a 42.0-kg female ice skater. They are at rest on the ice. They
push off each other and move in opposite directions. The female skater moves backwards with a
speed of 3.11 m/s. Determine the speed of the male skater (after collision)

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.