Do you have to overcome rolling friction when you slide a bag of groceries across the countertop?

Answer 1

If the bag is sliding across the countertop (i.e., the same surface of the bag is always in contact with the counter), then no. Rolling friction is only relevant when the surface of an object in contact with the surface it moves across always changes.

Answer 2

Rolling friction results from momentary attractions between a rolling object and the surface it is rolling on, so as long as the same surface of the bag is always facing the surface, as is usually true for sliding, there is no rolling friction to consider.

However, for sliding, there are two different values for friction: the static value, which is how much force must be applied to a resting object to start moving it across a surface; and the dynamic value, which is how much force must be applied to a moving object to make it keep moving with the same velocity.

Answer 3

No. Rolling friction is only relevant when the bag is rolling across the countertop. If the bag is sliding, then the same surface of the bag is always touching the countertop, instead of the surface constantly changing, as would happen for rolling.

Answer 4

no, you must overcome sliding friction.