hard spheres

[logistic_guy]

What is the effective cross section for the collision of two hard spheres of radius $\displaystyle R_1$ and $\displaystyle R_2$?

 

[khansaheb]

What is the effective cross section for the collision of two hard spheres of radius $\displaystyle R_1$ and $\displaystyle R_2$?

What is the definition of -

effective cross section for the collision

Please show us what you have tried and exactly where you are stuck.

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Please share your work/thoughts about this problem

 

[logistic_guy]

What is the definition of -


Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem

Thank you but no thank you!

What is the effective cross section for the collision of two hard spheres of radius $\displaystyle R_1$ and $\displaystyle R_2$?

The effective cross section denoted $\displaystyle \sigma$ is just the area of a circle whose radius is equal to the sum of the two spheres' radii. And the sum of the two radii represents the critical distance at which the surfaces of the spheres just come into contact during a collision.

Then,

$\displaystyle \sigma = \pi(R_1 + R_2)^2$

 

[khansaheb]

Thank you but no thank you!


The effective cross section denoted $\displaystyle \sigma$ is just the area of a circle whose radius is equal to the sum of the two spheres' radii. And the sum of the two radii represents the critical distance at which the surfaces of the spheres just come into contact during a collision.

Then,

$\displaystyle \sigma = \pi(R_1 + R_2)^2$

Now tell us what would be your next step?
Where are you stuck - exactly?

 

[logistic_guy]

Now tell us what would be your next step?
Where are you stuck - exactly?

I am exactly stuck on understanding the following:

When one's old balls are washed with bubble soap like Cherry smelling, how his left ball still smells differently than his right ball?