Gravity vs Inertia

[Cmac22]

Not really sure if this is the right place for this question but im sure you guys can answer it.

 

For the question im going to use a hypothetical situation:

say you have two small objects, like two apples, out it the middle of space very close to each other, and very far from any other object. because the closest objects are so far from these two apples, there would not be much other force (like gravity) effecting these two apples (right?). So my first question is would the gravitational pull from these two apples pull the apples together, or perhaps cause them to start orbiting or something?

 

Or would Inertia prevent these two apples from pulling together? i Asked someone this and they said that the inertia would prevent the objects from pulling eachother together.

 

That brought me to my second question:

The way i understand it, both Inertia and Gravity are affected by mass. the bigger the mass the bigger the pull of gravity and the more inertia it has. So, if you were to expand the two apples to the size of say planets, then

(i think?) the two apples would pull eachother together. But how is that possible if all we are chaning is the scale? because while the pull of gravity is bigger with the planet sized object, so is the inertia. is the answer that as mass increases, gravity increases more than inertia? if so what would determin the point at wich gravity overcomes inertia?

 

Sorry if this is all completely wrong haha

 

another possible answer to my own question might depend on the space between the two objects? i mean, if your scaling up the size of the objects than you also have to scale up the distance between them. so even with this distance scaling, what would happen?

[NeonBlack]

Incredible measurements have been made (1 part in 100 billion) which show that gravitational mass is exactly the same as inertial mass. That means as you increase mass, gravity increases in exactly the same way.

 

You probably know that all objects on earth have the same freefall acceleration. Say you have a 1 pound object and a 2 pound object. The force pulling the 2 pound object is twice as great. So why doesn't it fall twice as fast? Because it has twice as much inertia resisting the pull.

 

I hope this answers your question.

[Cmac22]

yes, thank you, that answers my question about how mass effects inertia and gravity. but it still doesnt answer (or maybe it does and i just havnt connected it yet) whether the two apples would pull together or not, as well as related questions

[NeonBlack]

Of course they will fall towards each other. As I said before, gravity and inertia scale exactly proportionally and an apple is just like a small earth. They would only orbit if their velocities were not exactly in the radial direction. So say they begin at rest some finite distance from each other, they will be pulled together.

[swansont]

You should be aware of the Cavendish experiment. Not quite down to the level of apples, but then, it was done over 200 years ago.

 

http://en.wikipedia.org/wiki/Cavendish_experiment

[Cmac22]

i c

 

thanks a lot!