Hint: Homework 04_Problem 11
Let’s examine this problem from the
point of view of someone on Venus. From
this point of view, the Sun orbits Venus counter-clockwise. At noon, our hypothetical Venusian would see
the Sun directly overhead … Now, if Venus DID NOT ROTATE, then the Sun would
have to travel 360 degrees completely around Venus in order to appear overhead
on the next day, i.e., the solar day on Venus would equal its ORBITAL PERIOD! Let’s call that time, TO.
But Venus
does rotate backwards … clockwise … or retrograde. So it will take LESS time than 1 orbital
period for the Sun to appear overhead again, because while it’s moving forward,
counter-clockwise, around Venus … Venus, itself, is rotating backwards or
clockwise. Let’s call the time it takes
for the Sun to appear overhead again, S, the time of 1
solar day.
Venus has
rotated backwards during a time S thru an angle of 360 S/TR, while
the Sun has moved forward thru an angle 360 S/TO, until the Sun
appears overhead again. What is the sum
of these 2 angles? If you can answer
that, you can find an equation and solve it for S. It really helps if you draw a picture!