If the total (PE+ KE) before an event is equal to the total (PE+ KE) after the event:
A. the PE must not change.
B. PE (before) = KE (before).
C. energy is conserved.
D. the momentum does not change
PLEASE HURRY

What is the temperature in degrees celsius of a substance with a tempature of 49k

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.

The magnitude of the amount of energy released by burning a fuel source, measured in energy per unit mass, is called its fuel value. note that the fuel value is the negative of the isobaric specific heat of combustion for the fuel. if all the energy obtained from burning 1.23 pounds of butane with a fuel value of 10.85 kcal/g is used to heat 128.0 kg of water at an initial temperature of 18.3 °c, what is the final temperature? note that 1 lb = 453.6 g.