.. Eugene wants to ride his bike at least 40 miles today. The first hour was mostly downhill, and he rode 13 miles. He has 3 more hours to ride.
Write and solve an inequality to find how many miles per hour Eugene
needs to ride to meet his goal.

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.