**ASTR430 HW#5 (due 11/23/05)**

- Problem #15 from Ch. 9 (p. 269).
*Hint: for part (a), just estimate the total mass excavated and compute the energy required to lift it 10 times the crater diameter. Assume the acceleration due to gravity over that height remains constant. You'll need to assume a bulk density for the material. For part (b), see Fig. 9-6.* - Problem #13 from Ch. 10 (p. 315).
*Hint: use the expression involving in the mathematical notes on p. 297.* - Don't forget your term project essay!

Derek C. Richardson 2005-11-09