Hot coffee in a mug cools over time and the mug warms up. Which describes the energy in this system?
The average kinetic energy of the particles in the mug decreases.
The average kinetic energy of the particles in the coffee increases.
Thermal energy from the mug is transferred to the coffee.

Question

Hot coffee in a mug cools over time and the mug warms up. Which describes the energy in this system?
The average kinetic energy of the particles in the mug decreases. 
The average kinetic energy of the particles in the coffee increases. 
Thermal energy from the mug is transferred to the coffee.

anonymous · Answer

I will go for C, due to conduction, whereby heat is transferred between particles as they are in contact.