Foo - Physics Help Please?

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BenLi
01-20-08, 09:21 PM
A cubical block vibrates horizontally, in Simple Harmonic motion (SHM) with an amplitude of 8.0 cm and a frequency of 1.5 Hz. If a smaller block sitting on it is not to slide, what is the minimum value that the coefficient of static friction between the two blocks can be.

Answer : 0.72

Can anyone help?

EJ123
01-20-08, 09:35 PM
Message Phantomcow2. He'll know.
stevesurf
01-20-08, 09:37 PM
In Coulomb Damping (http://en.wikipedia.org/wiki/Coulomb_damping), the frictional force each of the object's experience are opposite each other and equal. The Coefficient of static friction of the smaller object x the Normal Force (smaller object's weight) = the Frictional Force.

Find the equation that relates Force, Amplitude and Frequency of the larger object and solve for the Coeff. of Static Friction.

ElJamoquio
01-20-08, 09:52 PM
1. Figure out the acceleration with simple harmonic motion.

x = sin(wt)

Take the double derivative and find the mzximum. Hint, it should be really easy.


2. Figure out the force.

F = m*a = coefficient of friction * m
BenLi
01-20-08, 10:25 PM
thanks for the help all. I've solved it. Here's the solution in case you were curious.

http://i214.photobucket.com/albums/cc232/ben_li/Physics-2.jpg