# Coulomb's Law and the moon

1. Sep 10, 2007

### itzxmikee

1. The Moon and Earth are bound together by gravity. If, instead, the force of attraction were the result of each having a charge of the same magnitude but opposite in sign, find the quantity of charge that would have to be placed on each to produce the required force.

2. Fe = ke |q1||q2|/r^2

3. 9.81 = ke |x||-x|/r^2
solving for x, I ended up getting -.64766

Not sure if I understand the problem correctly or not. Please help steer in the right direction. Thanks

2. Sep 10, 2007

### bel

I think you need to equate the gravitational pull of the earth on the moon with $$F_e$$. Since you know the radius from the center of the earth to the center of the moon, and you know $$k_e$$, you can find the two "q"s by a simple square root operation, making one positive and the other negative.

3. Sep 10, 2007

### itzxmikee

I got it..thanks