At the microscopic level heat conduction is a chain of collisions by particles of different kinetic energies. Suppose a heat interaction occurs between a hot object of 80 °C and a cool object of 10 °C, and the primary energy transfer mechanism is heat conduction. If the interaction continues long enough, how will the average kinetic energy of the particles in the (initially) hot object compare to the average kinetic energy of the particles in the (initially) cool object? a. The average KE of the hot object particles will be greater than the average KE of the cool object particles. b. The average KE of the hot object particles will be the same as the average KE of the cool object particles. c. There is no way to determine the correct answer.

A2.9 kg lump of aluminum is heated to 95°C and then dropped into 10.0 kg of water at 5.0°C. Assuming that the lump-water system is thermally isolated, what is the system's equilibrium temperature? Assume the specific heats of water and aluminum are 4186 and 900 J/kg-K, respectively. Number i Units

For a planet to have an atmosphere, gravity must be sufficient to keep the gas from escaping The escape speed a particle needs to escape the earth's gravitational attraction is 1.1 x 10 m/s. The motion of projectiles never depends on mass, so this escape speed applies equally to rockets and to molecules in the earth's upper atmosphere. Part A At what temperature does the rms speed of nitrogen molecules equal the escape speed? Express your answer in kelvins. ΜΕ ΑΣΦΑ T- Submit Part B T- Request An At what temperature does the mms speed of hydrogen molecules equal the escape speed? Express your answer in kelvins. VAZO Submit ? K K

A small metal cube with a thermal mass mc and an initial temperature 0 is dropped into a container of water that is actively maintained at a constant temperature 0w. The cube quickly comes to rest on the bottom surface of the container. The bottom surface is maintained at a constant temperature 0 (note that this is different from 0w). The thermal resistance between the cube and the water is Rcw while the thermal resistance between the bottom surface of the container and the cube is RCB. The temperature of the cube is denoted by 0c. a) Draw the system schematic indicating the assumed directions of the heat transfer rates. Label all the nodes and system parameters. b) Derive the governing equation for the temperature of the cube, 0c. c) Where does to appear in the system schematic and how does it affect the governing equations? d) Calculate the steady-state temperature of the cube, css, assuming the following system parameters: 0o = 21°C, 0B = 6°C, 0w = 0°C, Rcw = 2°C/W, and RCB = 4°C/W