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Q & A: Weight on the moon

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Most recent answer: 01/16/2011
Q:
what is the formula if i want to find my weight on the moon with just using a paper and a pen
- Anonymous
A:

Hi there!

You can find out how much you weigh on the moon just by doing some math. First, you need to know your weight on earth. After knowing that, simply divide by 6 and you'll get your weight on the moon!

How does that work? It turns out that the gravitational pull on the surface on the moon is six times weaker than that on earth. That means that for every object with some mass (which is fixed anywhere you go because it is just the amount of material in the object), the gravitational force on it is six times smaller on the moon. This is because the gravitational pull on the moon's surface depends on the mass of the moon and its radius. The bigger its mass, the stronger the pull; and the larger its radius, the smaller the pull (because while standing on the surface, you are further away from the center). In fact, the gravitational pull decreases with the square of the radius.

The mass of the moon is 0.0123 of Earth's, and its radius is 0.273 of Earth's. To find the gravitational pull on the moon compared to Earth's, we put those numbers in the formula:

(ratio of masses)/(ratio of radii)^2

= 0.0123/(0.273)^2 = 0.165, which is approximately 1/6.

Thus, given any weight on the Earth's surface, you can divide by 6 to find its weight on the moon.

Hope this helps!

-Mae


(published on 01/16/2011)

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