Can Static Friction Do Positive Work? A Pen and Paper Experiment

In summary, the conversation is about a teacher asking students to demonstrate static friction doing positive work with a pen and a sheet of paper. Suggestions are made such as placing the pen on the paper and pulling it, or rotating the pen on the paper to create movement. The purpose and significance of this demonstration is unclear, as the teacher did not provide further details.
  • #1
Pathos_Verdes
4
0
I was left bewildered by a question our teacher left us to think about over the next week. He asked us how we can demonstrate static friction doing positive work, using a pen and a sheet of paper. Can anyone tell me how I can do this, and why this is so?
 
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  • #2
I'm not sure what you are asking for. Do you just need an example of static friction doing positive work?
 
  • #3
Pathos_Verdes said:
I was left bewildered by a question our teacher left us to think about over the next week. He asked us how we can demonstrate static friction doing positive work, using a pen and a sheet of paper. Can anyone tell me how I can do this, and why this is so?

Any vehicle is moved forward by static friction...
 
  • #4
How about the static friction force acting on a crate sitting on the flat bed of an accelerating truck? If the crate is not moving with respect to the truck, is the static friction force doing work??
 
  • #5
He didn't give us any other detail. Just those I have stated.
 
  • #6
I think he wants you to place a pen on a sheet of paper, then pull the paper with the pen not moving relative to it. :cool:

Or maybe he wants you to draw a sketch on the paper using a pen instead of a pencil. :eek::wink:

If it's the first case, what does this show, if anything?:bugeye:
 
  • #7
Pathos_Verdes said:
He didn't give us any other detail. Just those I have stated.

So put your pen on the paper and rotate it, or move it, so the paper starts moving.
That should do the trick.
 

1. What is static friction?

Static friction is a type of force that exists between two surfaces in contact with each other, preventing them from moving relative to each other.

2. How is static friction different from kinetic friction?

While static friction acts on stationary objects, kinetic friction is the force that acts on objects in motion.

3. How is static friction related to work?

Static friction can prevent an object from moving, meaning that work is not being done on the object. However, when an external force overcomes static friction and causes an object to move, work is done on the object.

4. How do you calculate the magnitude of static friction?

The magnitude of static friction can be calculated using the formula Fs ≤ µsN, where Fs is the maximum static friction force, µs is the coefficient of static friction, and N is the normal force exerted by the surface on the object.

5. How does the coefficient of static friction affect the magnitude of static friction?

The coefficient of static friction is a measure of the roughness of the surfaces in contact. The higher the coefficient, the rougher the surfaces and the greater the maximum static friction force that can be exerted between them.

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