The exact mass of the moon was not determined until the Apollo lunar orbiter went into orbit around the moon. They used the period and the orbital radius to find the mass. But since you already know the mass of the moon, if the spaceship was orbiting 499 km above the surface of the moon, how long did it take for the lunar orbiter to make one complete orbit?

Help please... I tried 3x and got them wrong.

whats ur answer?

I got 2.66 hours.

This post was edited by XylaMints on May 22 2013 02:44pm

I got 867s and 2.66hrs is wrong ... I don't know what to even do

Calculation [edit]

Small body orbiting a central body [edit]
According to Kepler's Third Law, the orbital period (in seconds) of two bodies orbiting each other in a circular or elliptic orbit is:

where:
is the orbit's semi-major axis, in meters
is the standard gravitational parameter, in
is the gravitational constant,
is the mass of the more massive body.
For all ellipses with a given semi-major axis the orbital period is the same, regardless of eccentricity.


wiki


This post was edited by saber_x3 on May 22 2013 04:09pm

I got 13.37 hours

I meant 1.04 hours.

Still really need help on this ... Nobody's gotten the right answer yet

mmm, can you give me the actuall problem? word for word that is.

The exact mass of the moon was not determined until the Apollo lunar orbiter went into orbit around the moon. They used the period and the orbital radius to find the mass. But since you already know the mass of the moon, if the spaceship was orbiting 499 km above the surface of the moon, how long did it take for the lunar orbiter to make one complete orbit?

Sorry I think I forgot to include the mass... Like an idiot

Moon

1.74E6 = Radius

7.35E22 = Mass.

mmm I got 2.63 hours.