The Inclined Plane

Normal Force

the surface pushes back

The ramp pushes out perpendicular to its surface exactly hard enough to cancel the block's press into it.

Example

The ramp pushes out perpendicular to its surface exactly hard enough to cancel the block's press into it.

highlighted = computed this step

The block presses into the ramp

From the last lesson, the block presses into the surface with 8 newtons.

W⊥=8 NW_\perp = \hl{8}\ \text{N}
The press into the surfaceA block on a ramp with one arrow pressing into the surface.minto-slope

The surface pushes straight back

The block does not sink into the ramp, so the surface must push out just as hard, perpendicular to the slope. That push is the normal force, equal to the press: 8 newtons.

N=W⊥=8 NN = W_\perp = \hl{8}\ \text{N}
Normal force balances the pressThe into-surface press and an equal arrow pushing out of the surface, perpendicular to the slope.minto-slopeN
mechanics The normal force simply equals the into-slope press, 8 N, because nothing moves perpendicular to the surface.