Problem 2: View the Dragon Beard video https://www.youtube.com/watch?v=auRNHI2nk

Question

Problem 2: View the Dragon Beard video https://www.youtube.com/watch?v=auRNHI2nkIU. Assume that when Dave Arnold pulls the Dragon Beard candy, he uses a force of 60 N and the first loop has an area of 1 cm2 . What is the stress on the candy? When he began the second pull, and there were two loops, what is the stress on each loop? What is the total stress? When he finished making the Dragon Beard candy, he made a total of 15,284 loops. What is the stress on each loop at that point? [Hint: Recall that the loop area decreases with each turn, and that he always exerts the same pulling force on the entire bundle of loops.)

Explanation / Answer

This question can be solved by using stress equation. As per stress equation

Stress (usually denoted by sigma) = F / A . Make sure to work convert to S.I units. However, you can use the given units. The answer will be in N/m2 or N/cm2.

Now, Area of loop = 1 cm2

Force applied = 60 N.

Then stress will be 60 N/cm2

After first loop, he makes a figure 8 to get two small loops with decreased area. As stress is inversely proportional to area. The stress will increase with decrease in area.

We need to know by how much loop area decreases which is not included in the question. Anyway, if you know this then you can easily find the stress for each loop using the same formula.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.