Homework Help: physics

Posted by mike on Friday, February 19, 2010 at 1:06am.

Small, slowly moving spherical particles experience a drag force given by Stokes’ law: where r is the radius of the particle, is its speed, and η is the coefficient of viscosity of the fluid medium. (a) Estimate the terminal speed of a spherical pollution particle of radius 1.00 x 10-5 m and density of 2000 kg/m3. (b) Assuming that the air is still and that η is 1.80 x 0-5 N · s/m2, estimate the time it takes for such a particle to fall from a height of 100 m.

physics - drwls, Friday, February 19, 2010 at 3:59am
You need Stokes' law to do that problem. You did not include it in the question, but I assume you have it or can look it up. (See also below) (a) The terminal speed of the particle is the value for which the Stokes' drag equals the weight minus the buoyancy force. (b) For the time to fall 100 m, divide 100m by the terminal speed.

The equations you need can be found at

http://en.wikipedia.org/wiki/Stokes'_law

Answer this Question

Related Questions

Physics - Small, slowly moving spherical particles experience a drag force given...
physics - Small, slowly moving spherical particles experience a drag force given...
Physics - A 50-kg person starts from rest at the top of a large frictionless ...
physics - "The actual value of computed g, assuming no drag, also varies ...
physics - Which of the following is correct for the charge in a magnetic field...
physics - Spherical particles of a protein of density 1.4 g/cm3 are shaken up in...
physics - Spherical particles of a protein of density 2.0 g/cm3 are shaken up in...
physics - An object is thrown upward at v0 from the surface of a small spherical...
physics - A metal sphere of radius r is dropped into a tank of water. As it ...
Physics - 1)The direction of the force on doubly ionized helium atoms(alpha ...

For Further Reading

First Name:
School Subject:
Answer: