## How to explain there cannot be a case where r=0 in F=G(Mm/r^2)

Hi. This is my first post here. In one of our science groups in Facebook, a member is asking about a case where r=0 in Newton's Equation F=G(Mm/r^2)

The best i could do was to state that there cannot be two point masses with a distance r=0 between them. He seems to accept my explanation but his intuition that it should be 'infinity' still remains. I would like to explain it better. Can you please help?

I have searched the site but could not find the answer. If there is already a thread, I would be glad if you could point me towards it.
 PhysOrg.com physics news on PhysOrg.com >> Study provides better understanding of water's freezing behavior at nanoscale>> Soft matter offers new ways to study how ordered materials arrange themselves>> Making quantum encryption practical
 Recognitions: Homework Help The gravitational force of attraction between two point masses, M & m2, separated by a distance 'r' is given by: F= GMm/r2 If r=0, then you don't have two masses anymore but one mass. In which cases, gravity would vary with depth of the planet. Read more here.

 Quote by WaaWaa Waa Hi. This is my first post here. In one of our science groups in Facebook, a member is asking about a case where r=0 in Newton's Equation F=G(Mm/r^2) The best i could do was to state that there cannot be two point masses with a distance r=0 between them. He seems to accept my explanation but his intuition that it should be 'infinity' still remains. I would like to explain it better. Can you please help? I have searched the site but could not find the answer. If there is already a thread, I would be glad if you could point me towards it.
When r=0, you no longer have two masses, you have one. This condition actually does occur at a black hole, where all mass is (believed to be) contained in a singularity, i.e., a single point.

## How to explain there cannot be a case where r=0 in F=G(Mm/r^2)

I don't think the gravity law works well on a quantum scale since the nuclear forces and electromagnetic forces become very strong at small distances.
 Thank you guys for your insights, we managed to resolve the question. When we are talking about classical physics, I think we sometimes tend to grab ideas from Relativity and Quantum Mechanics and get confused and this seems to be the root of the problem.