# physics

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1.An elastic cord is 5.0m long and 1.0cm in diameter and acts as a spring with spring constant 70 N/m, what is the young's modulus for this material?

2.A heavy uniform beam of mass 8000 kg and length 2.0m is suspended at one end by a nylon rope of diameter 2.5 cm and at the other end by a steel rope of diameter .64cm. The ropes are tied together above the beam. The unstretched lengths of the rope are 3.0 m each. What angle will the beam make with horizontal.

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Please present one question per post and show your work.

1. The amount of stretch is
(delta L) = F*L/(A E)
= 4 F L /( E pi D^2)

E is Young's modulaus
F is the tension force
L is the length
A is the cross ectional area

The spring constant is
k = F /(delta L)
= E pi D^2/(4L)

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