Two samples of carbon come into contact. A heat transfer will occur between sample A and sample B. What must be true for heat to transfer from sample A to sample B?

Heat flows spontaneously from the warmer sample to the cooler sample. Temperature reflects the particles’ average kinetic energy, so for heat to transfer from A to B, A must have a greater average kinetic energy than B. Thus, “The average kinetic energy of A is greater than that of B” is correct.

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