of approach) through visual inspection. Measure the length of the semi-major axis, a (to an accuracy of 0.5 mm).
[Hint: Draw the major axis, measure it in mm, and divide that measurement by 2 to get the length of a or the
semi-major axis. Remember that the major axis must go through two points: the center of the Moon’s orbit and the
Earth, which is one of the two foci of the ellipse.]
a = 20.8mm [Round to 1 decimal place.]
10. Remember, from Lab 4 you learned that c is the distance between the center of the ellipse (i.e., the Moon’s orbit)
and one of the
foci (here, the Earth). Measure c to an accuracy of 0.5 mm. (See the attached sheet on the ellipse if you need a
c = 26.3 mm [Round to 1 decimal place.]
11. The eccentricity of an ellipse is given by the equation e = c/a. Calculate the eccentricity of the Moon’s orbit from
measurements of a and c. Express your answer using 4 decimal places.
Note: Answers for questions
9–12 must be derived e = c/a = 1.2644[Round to 4 decimal places.]
from measurements made from the graph. Answers that are guesses or copied will NOT be accepted. 12. The
published eccentricity of the Moon’s orbit is 0.0549.
What percentage of the published eccentricity is your computed value? 12.64 % [Round to 1 decimal place.]
Scoring for Lab 6
If your value of e is less than the published value (0.0549), then the percentage must be less than Completing Table
1: 30 pts
100%. If your value of e is more than
the Plotting orbital points: 20 pts
published value (0.0549), then the
percentage Drawing smooth orbital curve thru plotted points: 05 pts
must be more than 100%. To