Cheryl runs a race on a circular 400.0 m track. she starts running east of the starting line and stops 20.0m west of the starting line. Her time is 8.0 × 10^1s. What is her average speed?

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.