Question

hi anyone please explain to me how stokes law works.
i've got these results and need help interpretting them.
diameters of balls 0.0650, 0.0190, 0.0055 gives terminal velocity of -6.625922752e+00, -6.625922752e+00, of -1.619002727e+00m/s . does this mean that as the diameter decreases the velocity at the which the ball is sinking is decreasing aswell?

Answer 1

@TuringTest @ganeshie8 @Callisto @perl

Answer 2

@iambatman @shrutipande9

Answer 3

@bibby @confluxepic @danish071996 @Mashy @ZippySlug

Answer 4

@FireWolfSpirit lol

Answer 5

Do you know what terminal velocity is ?

Answer 6

dude why are u asking me that? CONSTANT

Answer 7

You dont have to be rude.

Answer 8

@ Mashy @One098
i'm not being rude. sorry if it looked or sounded that way

Answer 9

It's fine. Just be careful because caps make it seem like you're mad.. or you're yelling. But its fine.

Answer 10

Constant what? :P

Answer 11

oh i see. but please can someone help me.

Answer 12

constant velocity

Answer 13

I'm not exactly clear on what you are asking. I see that you have data for sphere size and velocity, and you reference Stoke's law. So, what are you trying to understand?

Answer 14

that the diameter of the sphere affects velocity. i can see it does but would it be sensible to conclude that as the diameter of the sphere decreases the velocity also decreases?

Answer 15

You could just look at the data and conclude that. If you are asking about Stoke's law, I assume it's somewhere in your problem statement and you need to use it to justify that conclusion.
What does Stoke's law say?

Answer 16

i'm just trying to use stokes law. my problem definition is not stokes law it was just these equations given to us to solve terminal velocity of a falling ball through a fluid.

Answer 17

so i assumed it was stokes law. that's why i'm asking. we haven't learnt stokes law yet.

Answer 18

i have a maths test tomorrow, please can someone confirm that my assumption is right?

Answer 19

Yes, your assumption is right. If you want to get into exactly how it applies, we can do that. If you're just looking for confirmation, then yes, Stoke's law applies here and can be used to calculate the terminal velocity of spheres. The velocity will decrease with sphere size.

Answer 20

so velocity at which the ball sinks decreases or rise decreases as the sphere size deacreases?
such bad english

Answer 21

For spheres made of the same material and sinking in the same fluid, yes. A larger sphere will sink faster than a smaller sphere.

Answer 22

oh i see, i would really like to know the stokes law in detail but as of now i have a test tomorrow.
However before the exam i would want to discuss how stokes law with you.
see you then thanks bro! :)

Answer 23

I'm not on that often, so I likely won't catch up with you again before the test. But, in either case, good luck!

Answer 24

oh i see, well thanks .

Answer 25

bydaway just before i go, why does the larger sphere sinks faster? is due to drag?

Answer 26

I'll put the information in here so you can look at it later when you have the time.

Stoke's law says that the Force of friction on a sinking (or floating) sphere is proportional to the fluid viscosity, particle radius, and particle velocity. So the force increases linearly with the velocity and radius.

Terminal velocity occurs when the force of friction is balanced by the force of gravity (or buoyancy). The force of gravity is linearly proportional to the particle mass; the particle mass goes up as the Cube of the radius.

So, as the particle size doubles, the frictional force doubles but the gravitational force goes up by a factor of 8. This means that even though a larger particle will have more friction, it will be much heavier and will sink faster.

Answer 27

@ZippySlug thanks so much!

Answer 28

\(\huge\color{blue}{Welcome~To~OpenStudy!}\)
@zippyslug @E_S_J_F

Answer 29

@zippyslug
If you took that from a website then please cite your sources.

Answer 30

@confluxepic
I am a PhD candidate in Nanoscience and Microsystems Engineering with a minor in Chemical Engineering. No, I did not take that from a website. I understand fluid dynamics. Though it is all easily derived from the Stokes Law page on Wiki and an understanding of terminal velocity at the level of a 1st year undergraduate physics class.
https://en.wikipedia.org/wiki/Stokes%27_law

Answer 31

Okay then.