A sled slides down a hill with friction between the sled and hill but negligible alr resistance. Which of the following must be correct about the resulting change in energy of the sled Earth system? A) The sum of the kinetic energy and the gravitational potential energy changes by an amount equal to the energy dissipated by friction,
B)The gravitational potential energy decreases and the kinetic energy is constant.
C)The decrease in the gravitational potential energy is equal to the increase in kinetic energy
D)The gravitational potential energy and the kinetic energy must both decrease.