Find the density of a substance whose voume is 5cm3 and whose mass is 25 g

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Acar traveling at 22 m/s starts to decelerate steadily. it comes to a complete stop in 15 seconds. what is it’s acceleration?

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.