How big is the area of contact between a perfectly round circle and a perfectly flat line?

Question

How big is the area of contact between a perfectly round circle and a perfectly flat line?

Answer 1

One atom.

Answer 2

Ah. good question.  The mathematical term is called a point, and i think that is infinitesimal or 0. However, i guess it would depend how close you look at the contact point.  Shouldnt it go down to the microscopic/molecular level regarding surface contact.  In that case, it would depend on the material in contact with each other and their surface smoothness.

Answer 3

It would only be a single point.  Even if it appears to be a length of the arc, it isn't, because the arc is always curved, no matter how gradual it is.

Answer 4

Zero

Answer 5

it's just a point. Points have no area.

Answer 6

By definition, all circles are round and all lines are flat. Your phrasing makes me question if you are talking about geometry or not. If not, then the answer is that it depends on how wide you make your lines. If so, then the intersection of a circle and a line is either 0, 1, or 2 points, depending on whether or not they intersect at all, since you did not say that they intersect. In any case, points have no area, so the answer is 0.

Answer 7

theoretically, 0

Answer 8

although there are great answers here no one thing ever really touches another. There is a natural repell in the electrons of an atom to another, but that is whole physics lesson in itself.

Answer 9

In theory, their intersection would be a single mathematical point of zero dimension.

Answer 10

It is smaller than you can measure.

Every time you go to actually measure the contact area, I

can magnify it ten times, and your measurement is all wrong.

Answer 11

Lines are not flat.  A line is "extension without breadth" (Euclid).

The intersection of a line tangent to a circle is a single point - "position without extension" (Euclid).

A single point has zero area.