The following wheel consists of an outer ring (R) and an inner ring (r). The wheel moves clockwise by a force F applied to the inner ring as shown in the picture to make the wheel roll.
Draw the friction force.
The Attempt at a Solution
I could have sworn that if the wheel is turning clockwise as it moves, then the friction between it and the ground is drawn to the right because as it moves clockwise, the friction force would be directed counter-clockwise.
However my facit shows that the friction force is to the left:
Isn't this wrong? Shouldn't the friction force be drawn in the opposite direction? Or am I misunderstanding something here? (ignore the gravity and normal force in the drawing)
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