Which of the following statements about an apple falling from a tree is true? a) its kinetic energy decreases and its potential energy increases. b) its potential energy decreases and its kinetic energy increases. c) its kinetic and potential energies remain constant. d) its mechanical energy increases.

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

Gunpowder residue is most likely to show up where on a shooters hands

Aprotein molecule in an electrophoresis gel has a negative charge. the exact charge depends on the ph of the solution, but 30 excess electrons is typical. what is the magnitude of the electric force on a protein with this charge in a 1600n/c electric field? write in two significant numbers, and also in newton