How would you calculate the length of a year on a planet?

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SUMMARY

The discussion focuses on calculating the length of a year on a hypothetical planet using Kepler's Third Law, also known as "The Law of the Periods." Participants emphasize that the mass and radius of the planet are not directly needed for this calculation. Instead, the gravitational attraction equates to centripetal force, leading to the formula G M m / R^2 = m v^2 / R. The period of the planet's orbit can be derived from the orbital velocity (v) and the radius (R) of the orbit.

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songminho
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Homework Statement


How would you calculate the length of a year in Earth years on a hypothetical planet? (given the mass + radius of the planet)

I understand Kelper's law is used somehow, but is orbital velocity needed?
 
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Try Law #3, "The Law of the Periods".
The radius of the planet is a no-count. So is the mass.
 
You can start with: gravitational attraction = centripetal force
G M m / R^2 = m v^2 / R
I assume that by radius is meant the radius (mean) of the planet's orbit.
Note that the period can then be calculated in terms of v and R.
 

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