Problem 5.7 Comments
In case it isn't obvious, 1 A.U. = 1 Astronomical Unit
which (as a distance) is what you use for the radius
of Earth's orbit when
the orbit is assumed to be circular. You should make
such an assumption here.
DO NOT put a lot of numbers into your solution. Just
put your answer in terms of RE = radius of
Earth's orbit (1 A.U.) and TE = period of Earth's
orbit (1 yr) or something equivalent (e.g. omegaE
= 2 pi/TE). Don't feel you
need to convert to m/s or m/s2.
Note that if you do part (c) the way most people do,
integrating to show the answer it is the same as (a) is
pretty trivial.
A decent plot is expected for part (d). If
you don't have experience with computer plotting
packages, it is time to learn. Use A.U. as your
length unit for this plot and make sure the
x and y scales are equal.
Note: one sees the symbols A.U. or a.u. in other
contexts and it may mean "atomic units," "arbitrary
units," or perhaps something else entirely,
depending on that context. Normally one would
expect lower case letters for atomic units, upper case
for Astronomical Units and people should really avoid
using a.u. to abbreviate "arbitrary units" since it
is very confusing. Instead, use "arb. units." However
people, being people, sometimes do confusing things.