In tearing a paper towel or plastic bag

In summary, the force of a quick, sharp jerk when tearing a paper towel or plastic bag from a roll is more effective than a slow pull because it results in a greater acceleration and force. This is due to the principle of inertia, where the piece being pulled experiences a sudden change in motion while the rest of the roll remains unmoved. Additionally, the perforated edges of the paper towel or bag also contribute to its tear.
  • #1
pbody
41
0
1. In tearing a paper towel or plastic bag from a roll, why is a sharp jerk more effective than a slow pull



2. I found this answer online

A quick, sharp jerk means a greater acceleration and a greater acceleration means a greater force. And it is force that tears the paper towel or plastic bag


The Attempt at a Solution



I was thinking not only the force of the jerk like the answer online said but wouldn't it be as well because the roll is ƩF = 0 and the quick acceleration of the one piece while the rest remain unmoved?

I don't know if that is confusing sorry if it is.
 
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  • #2
Is the roll free to rotate?

If so ask yourself why the paper would ever tear?
 
  • #3
CWatters said:
Is the roll free to rotate?

If so ask yourself why the paper would ever tear?

I am making an assumption saying it is free to rotate, every single one I have encountered is. usually it tears because of the perforated edges. As well as I am assuming that the force and the jerk kind of the theory of the bus - when the bus accelerates you move forward and when it decelerates you move backward. the paper towel that you grabbed in my mind has the same theory its moving at a constant rate with a sudden change.
 
  • #4
I think the word you are looking for is "Inertia".
 
  • #5


Yes, you are correct in thinking that the force of the jerk plays a significant role in tearing the paper towel or plastic bag. When a force is applied to an object, it causes an acceleration, and in this case, a quick, sharp jerk causes a greater acceleration than a slow pull. This greater acceleration results in a greater force being applied to the paper towel or plastic bag, making it more likely to tear. Additionally, the sudden movement of the one piece while the rest remain unmoved can also contribute to the tearing process. This is because the sudden jerk creates a shear force, which is a type of force that acts parallel to the surface of the paper towel or plastic bag, making it easier to separate the layers and tear apart. Overall, both the force of the jerk and the sudden movement play important roles in the tearing process.
 

1. How does tearing a paper towel or plastic bag work?

Tearing a paper towel or plastic bag involves applying a force to the material in a specific direction, causing it to separate along a line of weakness or perforation.

2. Why does a paper towel or plastic bag tear in a straight line?

Paper towels and plastic bags are designed with a line of weakness or perforation that runs in a straight line, making it easier to tear in a controlled manner.

3. What causes a paper towel or plastic bag to tear unevenly?

If the force applied to the material is not evenly distributed, it can cause the material to tear unevenly. This can also happen if the material is already weakened or damaged.

4. Can tearing a paper towel or plastic bag create static electricity?

Yes, tearing a paper towel or plastic bag can create a small amount of static electricity due to the friction between the two surfaces. This is why you may sometimes see a small spark when tearing certain materials.

5. Is there a proper way to tear a paper towel or plastic bag?

The best way to tear a paper towel or plastic bag is to hold the material firmly with both hands and apply a steady force in one direction. Avoid jerking or pulling too quickly, as this can cause the material to tear unevenly.

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