Joe runs 30 meters in 5 seconds. He then rests for 15 seconds. Joe runs another 20 meters in 5 seconds. What is joes 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.

The radius of an atom is closest in size to a

7types of electromagnetic waves from lowest to highest frequency