======Friction of a Block on an Inclined Plane======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Categories:** {{$demo.categories}}
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**Alternative titles:** Block Sliding Down an Incline
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====Summary====                   
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====Procedure====  
  - Place one of the blocks on the flat incline.  
  - Slowly raise the incline until the block just begins to slide.  
  - Record the angle at which sliding starts; this corresponds to the coefficient of static friction.  
  - To measure kinetic friction, set the incline at a slightly greater angle and gently start the block sliding.  
  - Adjust the incline until the block moves at constant speed; record this angle to determine the coefficient of kinetic friction.  
  - Repeat the demonstration with different blocks and surfaces to compare results.



====Links==== 
Slide blocks down incline - UCSB Physics Lecture Demonstrations: 
{{youtube>5KpB2wCKkLs?}}\\

Dynamics Demo: Inclined Plane - Physics Demos: 
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📄 Slide blocks down incline - UCSB Physics Lecture Demonstrations: [[https://web.physics.ucsb.edu/~lecturedemonstrations/Composer/Pages/12.69.html]]\\

====Variations====
  * Use different block surfaces (wood, sandpaper, mylar, rubber, aluminum, polyethylene) to compare friction.  
  * Place a brass-clad plate on the incline to change the sliding surface.  
  * Try the smaller classroom version with an angle scale for easier measurement.



====Safety Precautions====
  * Ensure the incline is stable before releasing the block.  
  * Keep hands and fingers clear of the sliding block.  
  * Do not use very heavy blocks that could cause injury if they fall.




====Questions to Consider====
  * Why does the block remain at rest at small angles? (Because static friction balances the downhill pull of gravity until it reaches its maximum value.)  
  * Why is the angle for constant sliding different from the angle at which sliding starts? (Kinetic friction is slightly less than static friction.)  
  * How does changing the surface material affect the angle at which sliding begins? (Different materials have different coefficients of friction.)