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porschedude
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Homework Statement
A car is moving with constant velocity v, and has wheels of radius R. The car drives over
a clump of mud and the mud with mass m, and sticks to the wheel with an adhesive force of
f perpendicular to the surface of wheel. At what angle (theta) does the piece of mud drop off
the wheel?
Note that theta is the measure of the central angle of the circle.
Homework Equations
Fc=mv^2/R
The Attempt at a Solution
I am legitimately stumped on this problem, aside from my qualms with the question (the mud wouldn't drop off, it would fly off), this is what I have so far. I drew a free body diagram of the piece of mud. One force vector is pointing directly down. The other force vector (f) pointing toward the center of the wheel. Resolving into components:
ƩFx = fsin∅
ƩFy = fcos∅-mg
Thus, when recombining these components to determine the net force vector, I get
F = √ƩFx2+ƩFy2 in the direction of the center of the wheel, thus F=Fc=mv2/R
thus, after some algebra you can solve for theta. However, this yields only periodic values of theta that allow the force vector F to be equal to centripetal force, meaning, only at these periodic values of theta is the mud adhering to the wheel? I'm really lost, any help is much appreciated.
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