In liquids, friction is the resistance between moving layers of a fluid, which is also known as viscosity.In general, more viscous fluids are thicker, according to the journal Dysphagia, so honey ...

I'll be honest—friction is pretty complicated. Imagine that I have a block of wood sliding on a table. In some way, the atoms on the surface of the wood block are interacting with the surface ...

Friction is a contact force when two surfaces interact. The second equation is the kinetic frictional force that is used when two surfaces are sliding against each other.

To put it another way: Friction is to forces what Santa Claus is to a jolly man in a fat suit—window dressing on top of a very complex reality. This post originally appeared on Quora. Click here ...