# Normal forces

5 videos
1 skill
4A: How do forces work inside an elevator or when you slide a box across the floor? Normal forces are forces which act perpendicularly to surfaces. When you see a patient in a hospital bed, the reason he does not fall through the bed is because the ground provides the patient with a normal force that directly opposes the force of the Earth’s gravity on your the body (this is why you aren’t sinking to the Earth’s core right now). We will walk through real-world physical examples like these to shed light on normal forces.

### Normal forces questions

PRACTICE PROBLEMS
Normal forces questions

### Balanced and unbalanced forces

VIDEO 8:11 minutes
Primer on identifying balanced and unbalanced forces

### Normal force and contact force

VIDEO 7:18 minutes
The force that keeps a block of ice from falling towards the center of the earth

### Normal force in an elevator

VIDEO 11:49 minutes
How the normal force changes when an elevator accelerates

### Slow sock on Lubricon VI

VIDEO 4:47 minutes
What would happen to a slowly moving frozen sock on a frictionless planet

### Normal forces on Lubricon VI

VIDEO 7:12 minutes
Whether the normal force balances the force of gravity for a frozen sock or banana