- #1
bjnartowt
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Homework Statement
Period of Halley's comet is 76 years. It comes very close to teh surface of the Sun on its closest approach.
How far out from teh Sun is it at its farthest?
Homework Equations
- since no semimajor/minor axes data given: assume circular orbit.
- Earth orbit about Sun is: [tex]1.496 \times {10^{11}}m[/tex]
- Kepler's 3rd Law:
[tex]\frac{{{r_{Earth}}^3}}{{{r_{Halley}}^3}} = \frac{{{T_{Earth}}^2}}{{{T_{Halley}}^2}} = {76^2}[/tex]
The Attempt at a Solution
Plugging in the above numbers gives me a distance of:
r[HalleyOrbit] = [tex]2.68 \times {10^{12}}m[/tex]
Giancoli's back of the book gives:
r[HalleyOrbit] = [tex]5.4 \times {10^{12}}m[/tex]
My answer is approximately half of Giancoli's answer. I suspect I oversimplified the problem, but nothing is said of the geometry of Halley's comet to suggest I should use something other than a circle-orbit...although Giancoli says the comet comes "very close" to the Sun.
Am I missing something?