Normal Force
The perpendicular contact force exerted by a surface on an object pressing against it.
Governing formula
N = m g cos θ
SI unit
N
In depth
Normal force arises from microscopic electrostatic repulsion between electrons in contact surfaces, preventing solid bodies from passing through each other.
Examples in the real world
A table exerting a 98 N upward normal force on a 10 kg book resting on its top.