Section+7

=__//**Section 7- Friction Forces: The Mu of The Shoe**//__= toc

What Do You See?
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The picture is a girl pulling a shoe on ice and sand with a spring She is struggling to pull the shoe on the sand because there is less friction on ice.

What Do You Think?
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Some sports require special features on shoes based on the surface they play. For example, soccer uses cleat

Investigate
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1a. the shoe is a Nike Jordan flight size 13 basketball shoe. 6 N b. The wight the, bottom surface, the shape, 2a. We are going to see if the weight matters. We will do this by trying it with different weights in the shoe. We will record how many N it takes to move it. 3a. The table top surface is very smooth. b. 4 N c. .66666666666666666 4a. 8 N b. .66666666666666666 c. no it doesnt same amount of frictional force d. it wouldn't. 5a. 3N b. .375 N c. less d. heavier

Physics Talk
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friction- a force that resists relative motion between two bodies normal force- the force acting perpendicularly or at right angles to a surface coefficient of sliding friction- a dimensionless quantity symbolized by the Greek letter mu. Its value depends on the properties of the two surfaces in contact and is used to calculate the force of friction

Checking Up
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1. the force of friction is equal the newtons stay the same 2. the pulling force is equal to the frictional force because they were in opposite directions and the net force was zero 3. the coefficient of friction is the ration of two forces.

Physics Talk
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1. In track when it rains the surface becomes slippery but by wearing cleats with more friction it will be easier for the athlete 2. In ice skating you want less friction so you can slide on the ice 3. There will not be the same about of friction because different surfaces provide different amounts of friction. She will need to know the friction on both courts to see if they are similar so she knows if her shoes will still be perfect 4. it will be too much money to buy shoes for each surface and the same pair of shoes are close enough 5. 18N