# Magnitude of net Gravitational Force

1. Apr 26, 2017

### Jonwolf5400

http://file:///Users/jonwolf/Desktop/Screen%20Shot%202017-04-25%20at%207.42.22%20PM.png [Broken] 1. The problem statement, all variables and given/known data
a) What is the magnitude of the net gravitational force on the m2=10kg mass? Assume m1=20kg and m3=15kg.
b) What is the direction of the net gravitational force on the m2=10kg mass? Assume m1=20kg and m3=15kg.

2. Relevant equations
F = G*m2*m3/R^2

3. The attempt at a solution
M2 x vector force
sin(26.565)*G*m2*m3/(0.223)^2
M2 y vector force
cos(26.565)*G*m2*m3/(0.223)^2

Total force
x vector
sin(26.565)*G*m2*m3/(0.223)^2 = 9.03796*10^-8
y vector
G*m2*m1/0.2^2 + cos(26.565)*G*m2*m3/(0.223)^2
= 5.0058*10^-7

magnitude
sqrt((9.03796*10^-8)^2+(5.0058*10^-7)^2) =
5.0867

angle
Don't know

#### Attached Files:

• ###### Screen Shot 2017-04-25 at 7.42.22 PM.png
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Last edited by a moderator: May 8, 2017
2. Apr 26, 2017

### Staff: Mentor

Hi Jonwolf,

Welcome to Physics Forums!

Can you provide a drawing or description of the locations of the masses with respect to each other? Cartesian coordinates would work, too.

3. Apr 26, 2017

### Jonwolf5400

Just did it. Thought i did it the first time but it must have not went through. Thanks!

4. Apr 26, 2017

### Staff: Mentor

What is the 0.223 value? It looks like it might be the distance from m2 to m3, but shouldn't you be using the square of that distance?

Why don't you determine the angle θ = tan^-1(10/20) once and then use the symbol θ for it, rather than carrying the full expression along through your calculations?

You should provide intermediate values for examination, such as the values of the x and y components of the forces, so that helpers can check your steps.