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In a statics exam I had the question in the picture attacehd and I had some trouble understanding it. The question is so

Under the effect of torque Mo rotates a wheel (radius r) with constant velocity around point A. A brake jaw presses on the wheel (height c) . The brake jaw is connected to a tilted brake handle with inclination angle α . The break handle is articulated at point B and horizontally binned. On the other side the brake handle is supported by a sliding shoe against a vertical wall ( corfficient of friction µo) . The friction coefficient between the rotating wheel and the jaw is µ. The weight of the brake handle is neglected. The system in the above described state is in equlibrium.

I translated the question myself so execuse me if the formulation was a little bit messy. I have also attached a photo of how the answer should be.

What i don't understand is

1) why there is no reaction at the point B (the movable bearing)

2) why is the anticipated direction of brake handle motion is upwards and how the rotation of the wheel causing this motion

3) which component of the reaction of the wheel on the brake handle responsible for this motion ( normal or friction )

4) why is the moment at point A Mo=Rr, isn't the opposing moment by the friction force supposed to be less than Mo because the wheel is in motion and if the opposing moment is equal to Mo doesn't that mean the wheel is at rest

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