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What is the average speed

What happens in a global convection cell

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system

Efficiency is the ratio of to for a system a)power in to power in b)power in to power out c) power out to power out d) power out to power in