Types of Friction

Types of Friction

•Kinetic Friction• Is friction between moving surfaces• Sliding• Rolling• Fluid

Types of Friction

• Static Friction•When a force is applied to an object but

does not cause it to move

Pushing Books

• Try pushing a pile of five books across your desk with one finger• Place some pencils under the books, is it

easier or harder to move the books now?

Ways to Reduce Friction

• Switching From sliding kinetic friction to rolling kinetic friction• Example: Placing a large, heavy box on a cart with

wheels to move it instead of pushing it

Ways to Reduce Friction

• Lubricants: Substances that are applied to surfaces to reduce friction between surfaces• Example: Butter in a pan while cooking so that food

does not get stuck• Example: Adding water to a slide will make you go

faster because the friction is reduced

Soapy Hands

• Who can open a pickle jar? (or a jelly jar, or a cherry jar, or whatever kind of jar you wish!) • Who can open a pickle jar with soap on their

hand?• It is easier or more difficult with soap?

Ways to Increase Friction

• Make surfaces rougher• Putting salt on patches of ice in the winter so that you

do not slip• Wearing gloves in football so that you can catch the

ball more easily

Ways to Increase Friction

• Increase the force pushing the surfaces together• Pressing down harder while scrubbing a pan• Sanding wood with sandpaper will work better if you

are pressing down with more force

With your groups• Think of 3 examples where you can increase friction between

2 objects

• Think of 3 examples where you can decrease friction between 2 objects

*They cannot be the same examples we have used in class!! *

Exit Slip• Turn in to Ms. Crema to get your homework for the day!

• What is Friction?

• What are the 2 factors that affect the amount of friction between objects?

• What is one way we increase friction between 2 surfaces?

• What is one way decrease friction between 2 surfaces?