by calcguy » Mon Jan 31, 2011 9:28 pm
11Q-26. The average length of a time zone is 1/24th of the circumference of the latitude circle (Latitude "lines" are circles with centers on Earth's axis).
The equator is the 0° latitude circle. All other latitude circles have radii equal to the radius of the Earth (3960 mi) times the cosine of the latitude angle.
Here's the solution: 600 = 1/24 x 2π x 3960 x cosΘ → Θ = 54.6°
11Q-38. The given orbital periods have units of days/revolution. The reciprocal of the period is the rotational frequency with units revolutions/day. You can calculate the time between closest approach of Jupiter to Mars by dividing 1 revolution by their relative frequencies (subtract their rotational frequencies to get relative frequency) like this: 1/(1/686.98 - 1/4332.4) = 816.44 days. Now divide this time by Mercury's orbital period: 816.44/87.99 = 9.279 revolutions.