Phyiscs Question - Topic

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Nov 13 2014 10:14pm

I'm currently taking an online test and this is the only problem giving me trouble, can someone help me out?

Newly discovered planet-X takes 33 years to orbit the sun once. What is the average distance from planet-X to the Sun? (The distance from the Earth to the sun is 1.496 x 10^11 m.)

a. 7.9 x 10^11m
b. 5.2 x 10^11m
c. 1.5 x 10^12m
d. 9.7 x 10^11m

Dontrunaway

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Nov 13 2014 10:37pm

http://en.wikipedia.org/wiki/Orbital_period

mu = GM, which you equivilate with the Earth's value because the problem assumes the Sun is the same sun so you can remove it, along with 2 pi

T is in seconds, and earth takes 1 year

T1/T2 = sqrt(Eartha^3)/sqrt(a^3) solve for a^3
1/33 = 5.7863x10^16 / sqrt(a^3)
sqrt(a^3) = 1.9095x10^18
a = 1.5391x10^12

This post was edited by Dontrunaway on Nov 13 2014 10:38pm

DeviousX

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Nov 14 2014 03:29pm

Quote (Dontrunaway @ Nov 13 2014 08:37pm)

http://upload.wikimedia.org/math/5/0/f/50f9cad0c149bd3fe30446a17b834884.png http://en.wikipedia.org/wiki/Orbital_period

mu = GM, which you equivilate with the Earth's value because the problem assumes the Sun is the same sun so you can remove it, along with 2 pi

T is in seconds, and earth takes 1 year

T1/T2 = sqrt(Eartha^3)/sqrt(a^3) solve for a^3
1/33 = 5.7863x10^16 / sqrt(a^3)
sqrt(a^3) = 1.9095x10^18
a = 1.5391x10^12

thank you I appreciate it.

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