The useful idea
- The useful idea
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding or grinding against each other.
- How it works
Types of friction include dry, fluid, lubricated, skin, and internal – an incomplete list.
- Why it matters
The study of the processes involved is called tribology, and has a history of more than 2,000 years.
Why this matters
Look for Friction the next time you notice this pattern in everyday life.
Try this
Look for Friction the next time you notice this pattern in everyday life.
Test your recall
Which idea belongs to the explanation of Friction?
- Why it matters
- How it works
- The useful idea — correct
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding or grinding against each other.