In tearing a paper towel or plastic bag

pbody
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.

Homework Helper
Gold Member
Is the roll free to rotate?

If so ask yourself why the paper would ever tear?

pbody
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.