# Static and Kinetic FrictionPage 1

Slide 1

## Static and Kinetic Friction

Nerik Yakubov Robert Magee David Chen

Slide 2

## Instructional Objectives

Distinguish the Difference Between Static & Kinetic Friction

Solve Problems Involving Friction Effects

Slide 3

## What is Friction?

Force that acts oppose the relative motion of two surfaces

High for dry and rough surfaces

Low for smooth and wet surfaces

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## Free Body Diagram

Normal Force FN

Friction Force ff

Applied Force F

Gravity Force Fg

Fg = mg

FN = Fg

ff = F

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## Static Friction

FN

fs

F

Fg

The Force of Static Friction keeps a stationary object at rest!

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## Kinetic Friction

FN

fk

F

Fg

Once the Force of Static Friction is overcome, the Force of Kinetic Friction is what slows down a moving object!

Motion

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## Types of Friction

I better be safe Ump!!

To initiate motion of the box the man must overcome the Force of Static Friction

Upon sliding, the baseball player will come to a complete stop due to the Force of Kinetic Friction

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## Static & Kinetic Friction Coefficients

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Static VS. Kinetic Friction

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## Static Friction Lab Procedure

Connect the force detector to a block of wood

Pull gently on the force sensor unit the block begins to move

Move the block slowly with constant force

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Ideal Result

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## Kinetic Friction Lab Procedure

Line up the block with the motion detector

Push the block gently toward the motion detector so that it comes to a stop approximately 1 foot away from it

From the velocity curve determine the deceleration of the block

Calculate the Force of Kinetic Friction

Determine the coefficient of Kinetic Friction

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