There is a 5th questions that asks:5. What is the scale height of Earth's atmosphere if you assume it is all nitrogen molecules and take the temperature to be 300K? This of course a rough estimate, but with it describe what happens to the atmosphere the farther out it is from earths surface. Is the definition of the edge of space at 100km reasonable?

Homework assignment The escape velocity from a massive object is the speed needed to reach an infinite distance from it and have just slowed to a stop, that is, to have just enough kinetic energy to climb out of the gravitational potential well and have none left. You can find the escape velocity by equating the total kinetic and gravitational potential energy to zero E = >muesc - GmMir = 0 Vesc = V2GMIr where G is Newton's constant of gravitation, M is the mass of the object from which the escape is happening, and r is its radius. This is physics you have seen in the first part of the course, and you should be able to use it to find an escape velocity from any planet or satellite. For the Earth, for example the escape velocity is about 11.2 km/s, and for the Moon it is 2.38 km/s. A very important point about escape velocity: it does not depend on what is escaping. A spaceship or a molecule must have this velocity or more away from the center of the planet to be free of its gravity, 1. In the atmosphere of a planet or large satellite the hot molecules or atoms may be moving fast enough to escape the gravitational potential well that confines the atmosphere to the planet. Why does hydrogen escape more easily than carbon dioxide? 2. Consider the Earth and its atmosphere of nitrogen, oxygen, and carbon dioxide molecules. At a temperature of 300 K and above the Earth's surface near the edge of "space" ( roughly 100 km up), compare the mean speed of these molecules with the escape velocity from Earth's gravity. Are there any molecules out there that can escape? Explain your answer considering the Maxwell distribution of speeds. 3. With the Maxwell-Boltzmann distribution of velocity for atoms in a gas in mind, why does the Moon not have an atmosphere but the Earth does? 4. What happens to the hydrogen if water is dissociated into its constituent atoms by interaction with fast charged particles in the solar wind? A magnetic field March will deflect these particles and protect a planet from their effects