# What is Friction?

Ryan S.
2012

Facts on Friction
Friction is one of the most common forces in our lives but we don’t know all that much about friction. Friction is a force that happens when you rub two objects together. Friction opposes any attempted movement or motion. The size of the force depends on what the two surfaces are like. The force of friction between the objects is different than the speed as long as the two objects are moving.
Types of Friction

 Figure 1: Friction is pushing the book in the opposite direction keeping it from falling off the table.

Static Friction is the force needed to make something move that is not moving. Static Friction is also stronger than Kinetic Friction. Kinetic Friction is when the object in motion is slowed because of the resistance of movement. Rolling friction occurs when a cylinder ball or wheel is rolling over a flat surface. Fluid Friction happens when and object moves through a fluid. When an object rolls over a surface it is called rolling friction. Sliding Friction occurs when two surfaces slide against each other. Rolling Friction and Fluid Friction is easier to stop than sliding friction. The force needed to make every type of friction stop is different for all of them.

What Friction Does for Us

 Figure 2: Friction is opposing the guy who is pulling the box across the road.
For Example if you try to push a heavy box across the road friction will slow you down because of the rubbing force. Another example is a car. When you drive a car the brakes work because of friction. The tires basically stop moving and friction stops the car. Friction is the force that when you push something against another friction will push in the opposite direction slowing down or to a stop. If there was not friction the objects pushed together would keep moving and eventually slip. Most surfaces are not that smooth and that is one cause of friction. The rougher a surface is the more friction will affect it. A heavier object is going to have more friction than a lighter object because friction becomes stronger the more the two surfaces are pushed together.

What Friction Does for Us
Friction is an everyday force that everybody needs. Friction is the same force that happens when a firefighter slides down the pole as when you push a book across the table. When two surfaces rub against each other the force that is applied is called friction. Friction is everywhere. When you look around everything is effected by friction. Even when you walk friction is right under you keeping you from slipping. Friction is the force that pushes against the object moving against the surface. For example when you rub your hands together your hands become warm because of friction. If you try to rub them together fast friction will slow you down. When you walk friction pushes against your feet slowing your feet down and keeping your feet from sliding. If you tried to run down a hill in the winter and you try to stop on a patch of ice friction may slow you down but the ice makes the ground more slippery so you won’t stop you will just slide. If there was no friction everything would be slicker than ice. You would not be able to walk you would just simply fall on your butt. You would not be able to start a car and if did it would be practically impossible to stop. That is why we need friction so we won’t get hurt. Thanks to friction we are able to walk. Without friction the ground would act like a treadmill because your feet would just slide and not go anywhere. Without friction when you try to walk you slip. It’s just like when you spill a liquid on the floor or if you try to walk on ice that is a lot more slippery you will most likely slip because there is less friction. Friction always keeps us here and still. Without friction we would slip. A pulley also needs friction in order to work.

Glossary
Fluid Friction happens when and object moves through a fluid.
Kinetic Friction is when the object in motion is slowed because of the resistance of movement.
Rolling friction occurs when a cylinder ball or wheel is rolling over a flat surface.
Sliding Friction occurs when two surfaces slide against each other.
Static Friction is the force needed to make something move that is not moving.

Department of Physics. “Q&A What is Friction.” Ask the Van. University of Illinois. 2012. Web. 9/24/12.
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“friction.” Encyclopædia Britannica. Encyclopædia Britannica Online School Edition. Encyclopædia Britannica, Inc., 2012. Web. 20 Sept. 2012.