Is it possible for the friction force to point in the direction of motion?

Answer 1

Friction is a force that always works against motion. Just imagine pushing a box

across the floor. Does it slow down? Yes. This is because Friction is working against

the forward motion of the box.

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Let's think about this, and maybe we can figure it out . . .

Let's assume that friction works in the direction of motion. If that's true, then we're

in great shape! All we have to do is give something a little tiny nudge, just enough

to start it moving, and then friction would keep it moving. Or, if there wasn't enough

friction to keep it moving, then we could always make more friction . . . just set the

little object on a big board with sandpaper on the bottom, and then there'd be plenty

of friction, surely enough to keep it moving once we got it started.

That's not the way things work. So the friction must be acting in the other direction,

against the motion.

This analysis brought to you by: Reductio Ad Absurdum, and his orchestra.

Answer 2

Since motion is relative then yes friction can point in the direction of motion.

This would only work if the thing that is causing the friction is moving in the opposite direction to the force pushing the object.

An example is a person pushing a heavy box from the front to the rear of a fast moving train. Relative to the person pushing the box the frictional force is opposite to direction of travel but relative to a person standing next to the train the frictional force is the same direction as the box is travelling.

Answer 3

Sure. What happens when your car is rolling along down the street and the tires on one side

hit a rain puddle in the gutter ? That side gets slowed by friction with the water, and the car

pulls toward that side.

Answer 4

It opposes the direction of the motion. That's why an object slows down when it is moving and the kinetic energy turns into thermal energy because of the friction