What is the Tension and Stretching of Spider Silk in Equilibrium?

  • Thread starter Thread starter michael1291
  • Start date Start date
  • Tags Tags
    Equilibrium
AI Thread Summary
The discussion focuses on calculating the tension in three strands of spider silk and their respective extensions based on the spider's mass and the force constant of the silk. The calculated tensions are Ta = 100 mN, Tb = 78.2 mN, and Tc = 147 mN, but there are concerns about the accuracy of these values due to potential errors in significant figures or rounding. The participant questions the interpretation of angles between tensions, suggesting they may be more than 90 degrees, which could affect the calculations. There is confusion regarding the weight conversion from mg to N, leading to discrepancies in the expected results. The participant seeks clarification on their calculations and the correct interpretation of angles in the problem.
michael1291
Messages
5
Reaction score
0

Homework Statement


The stretchy silk of a certain species of spider has a force constant of 1.50 . The spider, whose mass is 15mg, has attached herself to a branch as shown in the figure.
Figure:
http://session.masteringphysics.com/problemAsset/1348379/2/5-70.jpg
a)Calculate the tension in each of the three strands of silk.
b) Calculate the distance each strand is stretched beyond its normal length.

Homework Equations


Worked with the equations: Tc=Tacos(30) + Tbcos(40) for vertical components where Tc=mg=147 mN. And for the horizontal Tasin(30) = Tbsin(40). Found the ratio and plugged back into the equations to find Tb and then Ta.


The Attempt at a Solution


Using the relevant equations, I derived Ta = Tb x 1.286 and ultimately got answers:
Ta=100mN, Tb=78.2mN, and Tc=147mN.
 
Physics news on Phys.org
re tensions: chech 147mN

re last part: use force = force constant x extension
 
Does that say check* 147 mN, in that it is an incorrect magnitude for Tc?
 
A mass of 15mg = 15/(1000) = 0.015grams = 0.015/(1000) = 0.000015kg and now multiply by 9.81 to give weight in N to give 0.000147N = 0.147mN
 
so it should come to .100mN, .0782mN, .147mN for Ta, Tb, and Tc respectively?
 
the answer needs to be in 2 sig figs. I put in .100, .078, and .15. A message came up and said "Term 2: Not quite. Check through your calculations; you may have made a rounding error or used the wrong number of significant figures."

I cannot find this error. Kept all numbers in my calculator.

Same response for the second part, in which I submitted .067, .052, and .098
 
I think that the angles were interpreted incorrectly.

The angle beteen tension A and tension B looks to me to be more than 90 degrees. So I think that the angles are 30deg and 70deg, together making up 100deg.
 
worked out. Thanks a lot
 

Similar threads

What are the tension forces and angles in this stationary equilibrium setup?
Replies
1
Views
4K

Hot Threads

Recent Insights

Back
Top