AP Physics
A centrifuge rotor rotating at 12000 rpm is shut off and is eventually brought to rest by a frictional torque of 1.50 m·N. If the mass of the rotor is 4.80 kg and it can be approximated as a solid cylinder of radius 0.0710 m, through how many revolutions will the rotor turn before coming to rest? How long will it take?
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a. calculate the moment of inertia for the rotor (solid cylinder). Personnally, I recmmmend changing rpm to radians/sec
Torque=momentI* angular acceleration
solve for angular acceleration.
Then,
wfinal=winitial+ angAcc*time
solve for time
displacement=winitial*time+1/2 angacc;*time^2
solve for displacement in radians, divide by 2PI to get revolutions.posted by bobpursley
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