When two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium w each other. This statement is called

(a) Hydrogen molecules (molar mass is equal to 2.016 g/mol) have vrms equal to 193 m/s. What is the temperature? (b) Much of the gas near the Sun is atomic hydrogen (H rather than H2). Its temperature would have to be 1.5107 K for the speed vrms to equal the escape velocity from the Sun. What is that velocity?

Compare the SI units of specific heat and latent heat and explain any differences.

A sample of gas with a thermometer immersed in the gas is held over a hot plate. A student is asked to give a step-by-step account of what makes our observation of the temperature of the gas increase. His response includes the following steps, (a) The molecules speed up. (b) Then the molecules collide with one another more often. (c) Internal friction makes the collisions inelastic, (d) Heat is produced in the collisions. (e) The molecules of the gas transfer more energy to the thermometer when they strike it, so we observe that the temperature has gone up. (f) The same process can take place without the use of a hot plate if you quickly push in the piston in an insulated cylinder containing the gas. (i) Which of the parts (a) through

A high—pressure gas cylinder contains 50.13L of toxic gas at a pressure of 1.40107N/m2 and a temperature of 25.0C. Its value leaks after the cylinder is dropped. The cylinder is cooled to dry ice temperature (78.5C) to reduce the leak rate and pressure so that it can be safely repaired. (a) What is the final pressure in the tank, assuming a negligible amount of gas leaks while being cooled and that there is no phase change? (b) What is the final pressure it onetenth of the gas escapes? (c) To what temperature must the tank be cooled to reduce the pressure to 1.00 atm (assuming the gas does not change phase and that there is no leakage during cooling)? (d) Does cooling the tank appear to be a practical solution?

A 1.00MT bomb exploded a few kilometers above the ground deposits 25.0% of its energy into radiant heat. (a) Find the calories per cm2 at a distance of 10.0 km by assuming a uniform distribution over a spherical surface at that radius. (b) If this heat falls on a person’s body, what temperature increase does it cause in the affected tissue, assuming it is absorbed in a layer 1.00cm deep?

In the chapter on fluid mechanics, Bernoulli's equation for the flow of incompressible fluids was explained in terms of changes affecting a small volume dV of fluid. Such volumes are a fundamental idea in the study of the flow of compressible fluids such as gases as well. For the equations of hydrodynamics to apply, the mean free path must be much less than the linear size of such a volume, adV1/3 . For air in the stratosphere at a temperature of 220 K and a pressure of 5.8 kPa, how big should a be for it to be 100 times the mean free path? Take the effective radius of air molecules to be 1.881011 m, which is roughly correct for N2.

Global warming will produce rising sea levels partly due to melting ice caps and partly due to the expansion of water as average ocean temperatures rise. To get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00 C. Assume the column is not free to expand sideways. As a model of the ocean, that is a reasonable approximation, as only parts of the ocean very close to the surface can expand sideways onto land, and only to a limited degree. As another approximation, neglect the fact that ocean wan-ling is not uniform with depth.

How many grams of coffee must evaporate from 350 g of coffee in a 100g glass cup to cool the coffee from 95.0C to 45.0C ? You may assume the coffee has the same thermal properties as water and that the average heat at vaporization is 2340kJ/kg(560cal/g). (You may neglect the change in mass of the coffee as it cools, which will give you an answer that is slightly larger than correct.)

A physicist makes a cup of instant coffee and notices that, as the coffee cools, its level drops 3.00 mm in the glass cup. Show that this decrease cannot be due to thermal contraction by calculating the decrease in level if the 350 cm3 of coffee is in a 7.00-cm-diameter cup and decreases in temperature from 95.0 to 45.0 . (Most of the drop in level is actually due to escaping bubbles of air.)