[b] If a chunk of space debris of mass Y grams (g) is moving at Z centimeters per second (cm/s), what is the momentum of this object in units of kilogram meters per second (kg m/s)?
[c] Make the calculation given by the speaker toward the end of the Lecture 03 video. What is the speed of our solar system’s orbit around the center of the Milky Way galaxy?
[d] The disk of the Milky Way galaxy contains roughly 200 billion (1 billion = 109) stars. The disk is not solid, but rather is a volume about 100,000 light-years in diameter (1 ly = 9500 billion kilometers) and 1000 light-years in thickness. What is the number density of stars in the Milky Way galaxy disk, in units of stars per cubic light-year? How about in units of stars per cubic km?
Draw a sketch if it would help your reasoning. Show your calculations, and remember that in this instance, your answers are significant to only one digit.
