Gravitational Force due to Earth, Moon, and Sun

[snb29]

1. Homework Statement

Part One:
Calculate the magnitude of the gravitational force between the Moon and an m = 6.45 kg mass on the surface of the Earth nearest to the moon. The distance to the center of the Moon from the surface of the Earth is 3.76×105 km and the mass of the Moon is 7.36×1022 kg.

Part Two:
Calculate the ratio of the magnitude of the gravitational force between an m = 6.45 kg mass on the surface of the Earth due to the Sun to that due to the Moon. The mass of the Sun is 1.99×1030 kg and the distance from the center of the Sun to the surface of the Earth is 1.50×108 km.

2. Homework Equations :

F = G*M1*M2/r^2
G constant = 6.67E-11



3. The Attempt at a Solution :

For part A, I used the gravitation formula, and had this equation:

F = ((6.67E-11)(6.45)(7.36E22))/(e.76E5)^2

I keep getting my answer to be 223.97 N, but this is apparently incorrect?
I have not yet attempted part B, because I want to troubleshoot what I am doing wrong with Part A first. I have correctly answered previous, similar questions but this one has me stumped. Any and all advice is welcome.

Thank you!

 

[gneill]

The constant G has units. What are they? It is important that the units of all your values correspond, otherwise a power of ten (or two, or three...) could creep into spoil the party.

 

[snb29]

AHH! I feel like such a moron! thank you so much! I knew it had to be something silly!