- #1

garylau

- 70

- 3

So 1/0=infinity ?

then F= infinite large in mathematical sense?

is that statement correct ?

thank

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- Thread starter garylau
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- #1

garylau

- 70

- 3

So 1/0=infinity ?

then F= infinite large in mathematical sense?

is that statement correct ?

thank

- #2

BvU

Science Advisor

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Mathematically you have a singularity.

- #3

garylau

- 70

- 3

But In reality i can have two mass put in r=0.000001m

Mathematically you have a singularity.

So the force still become very large?

- #4

What happen if i put r=0 into the formula F=(k)mm/r^2

then F= infinite large in mathematical sense?

is that statement correct to say F is infinitely large?

You cannot put in r = 0. That does not make sense. It does make sense to consider:

##\lim_{r \to 0}F = +\infty##. This means, intuitively, when ##r## approaches ##0##, ##F## becomes larger and larger (F grows without bound).

- #5

BvU

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Well, the masses become smaller too for such small particles. One micron diameter with a reasonable density gives a very small mass !But In reality i can have two mass put in r=0.000001m

So the force still become very large?

On even smaller scales still other things happen. Protons, for example have a mass of only 1.67 10

- #6

garylau

- 70

- 3

is it possible that the mass is very large but the r is very small?Well, the masses become smaller too for such small particles. One micron diameter with a reasonable density gives a very small mass !

On even smaller scales still other things happen. Protons, for example have a mass of only 1.67 10^{-31}kg and a diameter of 0.88 10^{-15}m. At such small scales other kinds of forces are much stronger.

- #7

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Yes. Moreover, in quantum physics mass is, in a certain sense, proportional to ##1/r##.is it possible that the mass is very large but the r is very small?

- #8

mfb

Mentor

- 36,106

- 13,051

Yes, then you get a very large force. But it is always finite. And if you want to put the masses too close, you have to consider quantum mechanics where the simple approach with a well-defined distance fails.is it possible that the mass is very large but the r is very small?

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