# Homework Help: Normal Force

1. Oct 29, 2006

### BSCS

I'm trying to think up situations that will help me understand more complicated situations...

Let's say I have:

a box
on a slanted slope
on a chair
on the floor

The floor exerts a normal force on the chair. But, equal to what?

is it:

a box $$m_{1}gcos\theta$$

on a slanted slope $$m_{2}g$$

on a chair $$m_{3}g$$

on the floor

Is it the sum of these?

Also, would motion of the box along the inclined plane affect the result? It would seem to be "no".

2. Oct 29, 2006

### Hootenanny

Staff Emeritus
Have you tried drawing a FBD?

3. Oct 29, 2006

### BSCS

Yes, and it/they were getting complex, so I wanted to get some feedback. I came up with the force exerted down on the chair as having an x component and a y component (different from what I posted). From there I was thinking I could apply that vector to the FBD of the chair and come up with my answer. Is such a "cascading of forces" approach correct?

4. Oct 29, 2006

### Hootenanny

Staff Emeritus
Yes, from what I understand you to have described that is correct. Perhaps if you posted you FBD's we could comment further.

5. Oct 29, 2006

### Staff: Mentor

Huh? Are you describing one situation (a box on a chair which is on a slanted slope?) or multiple situations? What are those masses?