Lesson 7


🟦  6.1  Introduction to Friction

So far, we have focused on two categories of forces:

In this unit, we will add shear force to our studies.Β 

A shear force is one that is parallel (or coplanar) to a plane or surface. The symbol for shear force is V.

Friction is a different type of contact force. It falls under the subcategory of shear force. It's a force that lies in a surface between two objects, and the friction vector points in the direction that opposes motion.Β 

We will use the symbol Ffr for friction.

❏ Categories of force

get new image from Lesson 1 - force

🟦   Review of key concepts from Physics I

You likely received an introduction to the basics of friction in your Physics I course.Β 

This tutorial will provide a brief refresher on principles of friction, with a focus on the applications that are pertinent to Statics.

In engineering practice, friction is often neglected. This is because it tends to aid static equilibrium. Engineers generally design systems that do not rely on friction for static equilibrium.

In Statics, we wish to study the effects of friction on certain systems in static equilibrium.Β 


start with the leaning ladder - why normal forces are perpendicular to the surface when friction is neglected

reference back LESSON 1 - FORCE and build on that language. friction vector is at 90 degrees from the normal force vector. dealing with inclined and curved surfaces can be a little tricky. xy vs x'y' systems. the normal force is normal to whatever surface is removed from the FBD


V = force parallel to a surface

N = force normal to a surface

(paste in infographic from slides)

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Explain the half arrow

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❏ Flipbook: x!)


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❏ Animation: x

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➜ Practice Problems

coming soon