Question

Please answer the following in about 50-100 words each. No need for equations, please explain in words.

1) In which situation must you do more work: inflating a balloon at sea level or inflating the same balloon to the same volume at the summit of Mt. McKinley? Explain in terms of pressure and volume change.

2) Imagine a gas made up entirely of negatively charged electrons. Like charges repel, so the electrons exert repulsive forces on each other. Would you expect that the temperature of such a gas would rise, fall, or stay the same in a free expansion? Why?

3) On a chilly morning you can �see your breath.� Can you really? What are you actually seeing? Does this phenomenon depend on the temperature of the air, the humidity, or both? Explain.

4) Give two examples of reversible processes and two examples of irreversible processes in purely mechanical systems, such as blocks sliding on planes, springs, pulleys, and strings. Explain what makes each process reversible or irreversible.

Answer 1

As we go higher altitude than sea level atmospheric pressure decreases. Here as we go to summit of Mt. McKinley which is at hegher altitude than sea level , Hence the perssure at summit of Mt. McKinley is lesser than sea level.

We have relation between pressure P , work done W and volume V.

W=PV

Here volume is same in both cases so the work done is depending only on the function of pressure.

So, as the pressure at sea level is higher than summit of Mt. McKinley Hence work done to inflate baloon at sea level is higher than that of summit of Mt. McKinley.