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rockchalk1312
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After a fall, a 77 kg rock climber finds himself dangling from the end of a rope that had been 15 m long and 9.1 mm in diameter but has stretched by 2.3 cm. For the rope, calculate (a) the strain, (b) the stress, and (c) the Young's modulus.
strain = ΔL/L
stress = F/A
Young's modulus = (F/A)/(ΔL/L)
I haven't gotten any of these right and I have no idea what I'm doing wrong on them.
a) 2.3 cm = .023 m / 15 m = .0015
b) A = ∏r2 = (∏)(.0091/2)2 = 6.503E-5 m2
stress = ((77)(9.8))/(6.503E-5) = 1.16E7 N/m2
c) (754.6/6.503E-5) / (.023/15) = .756
None of those were right; also I thought Young's modulus was supposed to be a huge number so obviously that's not right. Any help is appreciated!
strain = ΔL/L
stress = F/A
Young's modulus = (F/A)/(ΔL/L)
I haven't gotten any of these right and I have no idea what I'm doing wrong on them.
a) 2.3 cm = .023 m / 15 m = .0015
b) A = ∏r2 = (∏)(.0091/2)2 = 6.503E-5 m2
stress = ((77)(9.8))/(6.503E-5) = 1.16E7 N/m2
c) (754.6/6.503E-5) / (.023/15) = .756
None of those were right; also I thought Young's modulus was supposed to be a huge number so obviously that's not right. Any help is appreciated!