Static Friction

1 / 9

# Static Friction - PowerPoint PPT Presentation

Static Friction. Holding in Place. Objects on an incline will often stay put. There must be a force that holds the object in place. Static friction is from the contact of resting objects. Force holds up to a certain point Force is based on the type of contact (rough, smooth)

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' Static Friction' - deacon-rosario

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Static Friction

Holding in Place
• Objects on an incline will often stay put.
• There must be a force that holds the object in place.
• Static friction is from the contact of resting objects.
• Force holds up to a certain point
• Force is based on the type of contact (rough, smooth)
• Maximum force is proportional to the pressing force of the object (normal force)
Inequality
• The approximate formula for static friction is:

ms is the coefficient of static friction

• This is an inequality.
• The force of static friction is generally less than the coefficient times the normal force

m

q

Starting Motion
• If Ffr < msFN = msmg cosq, then the block will hold.
• At equality the block just begins to move.

Forces balance on mass 1

Tension is equal on the rope

Forces balance on mass 2

m1

m2

Measuring Friction: Pulley

FT

Frope

FT

Frope

One component of gravity balances the normal force

The other component of gravity balances friction

m

q

Measuring Friction: Incline
Normal Force and Friction
• Static friction depends on both the normal force and on the coefficient of friction.
• To reduce friction requires reducing one of those factors.
• Reduce normal force by lightening the load