Q: why does a sheet of sandpaper become warm when you rub it against a wooden board?
possible answers: a. heat in the air is transferred to the sandpaper, b. matter in the sandpaper is converted into heat, c. the chemical energy in the wood is converted to thermal energy, d. the mechanical energy of the moving sandpaper is converted to thermal energy

Nitrogen (n2) undergoes an internally reversible process from 6 bar, 247°c during which pν1.2 = constant. the initial volume is 0.1 m3 and the work for the process is 121.14 kj. assuming ideal gas behavior, and neglecting kinetic and potential energy effects, determine heat transfer, in kj, and the entropy change, in kj/s. show the process on a t-s diagram.

Aball thrown by ginger is moving upward through the air. diagram a shows a box with a downward arrow. diagram b shows a box with an upward arrow. diagram c shows a box with a downward and upward arrow equal in size. diagram d shows a box with a downward and upward arrow with the downward arrow larger in size. which force diagram represents the forces on the ball? you may neglect the effects of air resistance.

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this