Describe how ultraviolet light degrades plastics and why it does ...

[robinn137]

Describe how ultraviolet light degrades plastics and why it does not generally degrade metals.
 
  What will be an ideal response?

Question 2

A stress-strain experiment was done on a plastic and the following data was noted on the plot of the experiment: ultimate tensile strength = 9000 psi, yield strength = 5000 psi, proportional limit = 4000 psi, strain-to-failure = 0.025, strain at yield = 0.020, stain at proportional limit = 0.015 . The original length of the sample was 4 inches. What was the modulus?
 
  What will be an ideal response?

[jordangronback]

Answer to Question 1

Ultraviolet

Answer to Question 2

The modulus is calculated by examining only the slope of the stress-strain curve before yield, that is before and non-linear behavior is seen. Hence, the slope at the beginning of the experiment is stress at yield (5000 psi) divided by strain at proportional limit

[robinn137]

Thanks for the timely response, appreciate it

[xiazhe]

Excellent