Direction of Friction in Rolling Objects

[Nyhm]

I have a question that seems to best fit into this thread.

I'm only concerned with the direction of friction. I believe that as you accelerate down the road the fs is forward for the wheels subjected to torque and backwards for the wheels being 'pushed'. If i have that right then my question is when the brakes are applied and assuming there is not any slipping (the car gradually slows down) are the forces of friction switched? Meaning, do the tires under torsion have a frictional force opposing the velocity of the vehicle?

 

[NoPoke]

The directions of the forces associated with friction between a pair of surfaces always acts to reduce the relative motion between the two surfaces. To apply this to a situation where there is no slip imagine the motion that would take place if friction between the two surfaces was zero.

 

[Doc Al]

I have a question that seems to best fit into this thread.

I'm only concerned with the direction of friction. I believe that as you accelerate down the road the fs is forward for the wheels subjected to torque and backwards for the wheels being 'pushed'. If i have that right then my question is when the brakes are applied and assuming there is not any slipping (the car gradually slows down) are the forces of friction switched? Meaning, do the tires under torsion have a frictional force opposing the velocity of the vehicle?

Yes, you are correct.