how to predict direction of friction in rolling motion

Question

surry99 · Answer

The general rule is that the force of friction acts tangent to the contacting surfaces in a direction opposed to the relative motion or tendency for motion of one surface against another.
Wheel problems can be tricky and it is best to practice drawing a lot of FBD for a variety of problems. Ex: wheel rolling from left to right on the ground, wheel rolling up an incline, wheel rolling down an incline etc.

surry99 · Answer

The rule is that the force of friction acts tangent to the contacting surfaces in a direction opposed to the relative motion or tendency for motion of one surface against another. Wheel problems can be tricky and it is best to practice drawing a lot of FBD for a variety of problems. Ex: wheel rolling from left to right on the ground, wheel rolling up an incline, wheel rolling down an incline etc.

anonymous · Answer

the way that i currently use is that i predict the direction of friction if the object were to slip and use the same direction for rolling.

anonymous · Answer

But i don't understand how the friction points forward in the case of a car accelerating from rest while it points backwards for a cylinder rolling downhill ,starting from rest.

surry99 · Answer

sketch a few cases and we can go over them

anonymous · Answer

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