I used to know that μ_{s}N is the maximum frictional force when it is a STATIC frictional force, but F_{fric} can be everything, from 0 to μN. The kinetic frictional force is always μ_{k}N.
If the cylinder moves in pure-roll, the force must be a static friction, doesn't it?
I'm so sorry but I can't figure it out.
I think that having a pure roll RELATIVELY to the platform, just means that its center of mass isn't moving, it only rotates about the CM. But for a_{cyl} to be 0, F_{fric} also has to be 0, and this is impossible.
thank you for help, i forget it...
Thanks, but I've already done this things. I am convinced that I'm doing somethig wrong.
Because my equations for the platoform are
F - F_{fric} = m a_{plat}
N = m*g + N_{1}
where N_{1} is the normal reaction on the cylinder, and N is the normale reaction of floor to the platform.
Now...
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