# Homework Help: Gravitational lines of force for two equal point masses?

1. Jan 24, 2010

### ILoveCollege

Gravitational "lines of force" for two equal point masses?

1. The problem statement, all variables and given/known data
"Sketch the gravitational "lines of forces" for two equal point masses. These are isomorphic to the electrostatic lines of force of
A. Two equal "+" point charges.
B. No pair of point charges separated by the same distance.
C. Two equal "-" point charges."

2. Relevant equations
None; E= F/Q; E=KQ/X^2

3. The attempt at a solution
My only question is wouldnt two "+" point charges and two "-" point charges have the same electric field line diagram?

2. Jan 24, 2010

### xcvxcvvc

Re: Gravitational "lines of force" for two equal point masses?

Yes, except the arrows will point in opposite directions, because the arrow points along the route a positive charge would take if placed in that spot. Would a positive charge move in the same direction regardless of if the two point charges making the field were both positive or both negative?

3. Jan 24, 2010

### ILoveCollege

Re: Gravitational "lines of force" for two equal point masses?

Yes? Whats choice "B" trying to state?

4. Jan 24, 2010

### xcvxcvvc

Re: Gravitational "lines of force" for two equal point masses?

The yes was directed toward your "only question." B is worded awfully weird, but I assume it means 1 + and 1 - charge.

5. Jan 24, 2010

### ILoveCollege

Re: Gravitational "lines of force" for two equal point masses?

So , intuitively, two "+" equal charges would represent the lines of the electric field for two equal point masses because two "-" charges would mean that electric field lines would have to show up out of no where and thats not possible. Correct?