The mass of the earth is 6x10^24 kg and its radius is 6400 km. What is the mass of a man weighing 977 N in a spring balance.

During cooling, the kinetic energy of the molecules falls. why does this happen? a.the motion of the molecules increases. b. the motion of the molecules slows down. c.the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.