Gravity on something with just about no information

[Hypnos_16]

Three uniform spheres are located at the corners of an equilateral triangle. Each side of the triangle has a length of 1.13 m. Two of the spheres have a mass of 2.97 kg each. The third sphere (mass unknown) is released from rest. Considering only the gravitational forces that the spheres exert on each other, what is the magnitude of the initial acceleration of the third sphere

I don't know what to do here
I feel as though the question is giving me not enough information
I don't have a Mass of the third sphere, or an acceleration or the force.
I don't even know where to begin.

 

[D H]

There is plenty of information here.

What makes you think you need the mass of the third sphere to solve this problem?

 

[Hypnos_16]

i thought i would need some information about the third sphere in order to solve it, but if not please help me.

 

[D H]

Ignoring air resistance, a tiny feather and a huge boulder each released from 1.13 meters above the ground experience the same acceleration when they fall toward the Earth.

Why is that?

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When you made this post you were given a template to follow. There was a warning right above the window in which you typed your entry, in big bold letters, stating "Use the template provided. If you don't, your post may be deleted!"

I'll give you a chance here to follow that template. What are the relevant equations for this problem? What work have you done to solve this problem?

 

[Hypnos_16]

Because Acceleration is Constant and acts the same on everything despite the size or weight...
So if i find the acceleration acting on one of the masses it should be the same on the other one to?

 

[D H]

One more time: What are the relevant equations here?

Once you answer that question, try to use them.

 

[Hypnos_16]

A = GM / r^2 is the equation for Acceleration due to Gravity, so would it just be twice as much since there are two forces pulling on it? or does that not matter?

 

[D H]

That's better. The answer is not two time GM/r². Acceleration is a vector, not just a magnitude. You need to account for the direction.

 

[Hypnos_16]

I got an Answer of 1.55x10^-10m/s^2 but I'm not given any directions, so how do i know which way it's going...I just tried the answer i got and got that it was wrong... did i do something wrong?

 

[D H]

Don't just guess!

How did you get that result? Did you account for both of the spheres toward which the third cube is attracted? Did you account for the fact that the three spheres are at the vertices of an equilateral triangle?

 

[Hypnos_16]

no, i didn't i got the acceleration created by one of the sphere's gravitational force, and used that answer, using the equation A = MG / r^2 to find A