# Coefficient of static friction

1. Nov 27, 2014

### AwsmAssassin

• Warning: Posting template must be used in homework sections of Physics Forums.
I have to make 2 ramps of 30 cm long along with 2 objects(objects need to be 8 cm long). One must be slippery so that it has a low coefficient of friction and one needs to be sticky and have the highest coeffivient of friciton possible. Bassically we place object on ramp raise it from one side so that the highest/lowest angle is achieved for the sticky/slippery objects. so, I need 1 object that will be the "stickiest", and one that needs to be most "slippery". Any help is appreciated, we are supposed to use low budge items. I tried to research for this, but i can't seem to find alot of information on low bugdet items :/
later edit : can't use objects that will disintegraate (water/ice) and the effects must be reproducilbe, aka, over and over and over again.
im sorry if this is a bit un professional post but I tried my best to explain it as well as I could

2. Nov 27, 2014

### haruspex

Have you looked at http://blog.mechguru.com/machine-design/typical-coefficient-of-friction-values-for-common-materials/? [Broken]

Last edited by a moderator: May 7, 2017
3. Nov 28, 2014

### CWatters

Perhaps...
Pencil erasers glued together to make one 8cm long (super glue should work)?
Sandpaper glued to wood block?

4. Nov 28, 2014

### haruspex

Except, that's not friction. No normal force should mean no lateral force.

5. Dec 2, 2014

### CWatters

Perhaps I wasn't clear. A pencil eraser or sand paper has pretty high friction when resting on most surfaces.

6. Dec 2, 2014

### haruspex

Ah, I see what you mean. If a very high friction is achieved, the object will have to be very shallow, or it will simply tip away from the slope. I guess that's why you suggest gluing erasers together to make a long one.

7. Dec 4, 2014

### CWatters

The OP said they had to be 8cm long.

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