60 Unit 7 Practice and Assessment

Outcome 1

1) A person with a weight of 715 N  hangs from a climbing rope 9.2 mm in diameter.

a) What is the of the rope in m2?

b) What is the applied to the rope?

 

2) A particular 60 climbing rope stretches by 0.15 when a 715 N person hangs from it.

a) What is the in the rope?

b) What is the strain in the rope as a percentage?

 

3) Label the following features in the stress-strain curve of a hypothetical material seen below:

  • Toe region
  • Elastic region
  • Yield point
  • Plastic Region
  • Ultimate Strength
  • Rupture Point
  • Failure Region
Stress in units of MPa plotted against % strain. The linear region runs from roughly 2.5% and 2 MPa to 5.5% and 10 Mpa.
Data adapted with permission from rubber band stress-strain data originally acquired by Umpqua Community College Students: Brittany Watts, Ashlie DeHart, Hanna Wicks and Juan Martinez.

Outcome 2

4) Use the data in the previous graph to determine the of the hypothetical material. Be sure to convert the strain from  % stretch back to fractional stretch before doing your calculations.

 

Outcome 3

5) Answer the following questions regarding the material used to create the created the stress-strain graph above.

a) How much force could be applied to a 2 m x 2 m x 10 m long block of this material before reaching the ?

b) When operating in the , how much additional stress would be required to cause an additional  strain of 0.01?

c) What force would cause that amount of stress you found in part b on the 2 m x 2 block?

d) What actual length would the 10 m long material stretch when put under the strain of 0.01?

e) What is the effective of this 2 m x 2 m x 10 m long block of this material?

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