- #1
Del8
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Hello,
I would like to be sure about my rotationnal velocities w1(t) and w2(t):
http://imagizer.imageshack.us/v2/800x600q90/912/c6X2du.png [Broken]The black arm is turning clockwise at w1. The blue disk is turning at w2 with w2 < w1. w1 and w2 are in labo frame reference. The disk is turning around itself counterclockwise at w2'=w2-w1 in the arm frame reference.
I1: inertia of black arm+disk
I2: inertia of the disk
F: force from friction
r: radius of the disk
t: time.
I guess no friction elsewhere than between disk and black arm. I guess that the force F from friction is constant even rotationnal velocities are changing, just for simplify calculations. Friction gives forces F1 and F2.
For me, while w2<w1 and while the force F can be constant :
w1(t)=w1-Frt/I1
w2(t)=w2+Frt/I2-Frt/I1For you, is it ok ?
I would like to be sure about my rotationnal velocities w1(t) and w2(t):
http://imagizer.imageshack.us/v2/800x600q90/912/c6X2du.png [Broken]The black arm is turning clockwise at w1. The blue disk is turning at w2 with w2 < w1. w1 and w2 are in labo frame reference. The disk is turning around itself counterclockwise at w2'=w2-w1 in the arm frame reference.
I1: inertia of black arm+disk
I2: inertia of the disk
F: force from friction
r: radius of the disk
t: time.
I guess no friction elsewhere than between disk and black arm. I guess that the force F from friction is constant even rotationnal velocities are changing, just for simplify calculations. Friction gives forces F1 and F2.
For me, while w2<w1 and while the force F can be constant :
w1(t)=w1-Frt/I1
w2(t)=w2+Frt/I2-Frt/I1For you, is it ok ?
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