A volunteer is holding a rapidly rotating horizontal bicycle wheel with two handles as shown. The volunteer rotates the bicycle
wheel so that the upper hand holding it becomes the lower hand.
What effect does this have?

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.

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

Aspacecraft that renters the earth’s atmosphere drastically slows down. the amount of kinetic energy the spacecraft has as it reenters the earths atmosphere