Answers to Problem Set 1

Solutions:

Ch. 1
Ch. 2 (My apologies for the two diagonal pages, but the errors are on the CD, and we can't fix them.)
Ch. 3 (See the note for 3-32 in the answers below.)

You can find answers to the odd-numbered problems in the back of your text. But for the even numbered problems:

1-14. A total of 1.1 x 10³ acre-feet fell.

1-16. a) 1 AU = 4.85 x 10^-6 pc = 1.58 x 10^-5 ly; b) 1 pc = 1.91 x 10¹³ miles; 1 ly = 5.87 x 10¹² miles.

2-58. Yes, there's a collision. The trains require 1000 m clearance to stop without hitting.

2-68. a) v_o = 3.70 m/s b) v = 1.74 m/s c) y = 0.70 m, which is 0.16 m higher

2-82. How about 95 g's? Ouch.

3-32. This is a proof, and since I don't like the solution on the CD, I'd do it like this:

Set c = a + b and d = a - b. Since c and d are perpendicular, their dot product is zero. Do the dot product by component, setting each component equal to the sum or difference (e.g. c_x = a_x + b_x) and work out the result. You should wind up with a_x² + a_y² = b_x² + b_y², which can only be true if |a| = |b|.

Home