# Friction Question

1. Oct 24, 2005

### Zee Student

My question is in regards to the forces of friction.

Following Newton's Third Law, every force should elicit another force.

If I were to let's say push a crate, I would exert a force upon the crate. Therefore the crate would exert a force upon me.

If the reason I have to apply force to move the crate or if I'm not even able to move the crate is because of the force that friction is eliciting in the opposite direction as me, then what is the corresponding third law force for it?

More succinctly, what is the reaction force from the force of friction and to what is it applied to?

Thank you very much to anyone who can respond. Boggling my damn mind.

And as this being my first post, I'd like to say this is an awesome forum and look forward to learning much here.

Last edited: Oct 24, 2005
2. Oct 24, 2005

### Staff: Mentor

To find the "reaction" force to any "action" force, use this version of Newton's 3rd law:
If body A exerts a force on body B, then body B must exert an equal (but opposite) force on body A.​
For the friction force, ask yourself what object exerts the friction force on the crate? Then what must be the "reaction" force?

3. Oct 24, 2005

### Zee Student

Thanks for the response.

So the friction (the floor) exerts its force on the crate, in response the crate exerts its reciprocal force on the floor but due to it's immense mass it's neglible?

4. Oct 24, 2005

### Staff: Mentor

The forces are equal and opposite: The floor exerts a frictional force on the crate; the crate exerts an equal frictional force on the floor. (This force will have a negligible effect on the motion of the floor/earth, but will be significant for the crate.)

5. Oct 24, 2005

### Zee Student

Ah, thanks Doc.