Lecture 13 Homework Problems

1. The text uses the relation vrms > vesc/6 for the velocity needed to lose a component of the atmosphere, and from that obtains equation 19.6. Using the relation given in the lecture (vrms > vesc/10), how would equation 19.6 be modified? Give the new equation.

2. The Moon cannot hold on to water vapor (H2O) or oxygen molecules (O2) because it is too small. Referring to the example calculation for the Moon done in the lecture, how much more massive would the Moon have to be to retain O2? How much more massive would it have to be to retain H2O? Express your answer in units of the Moon's mass.