Converting from lb_f/in to N/m issues

  • Thread starter Dustinsfl
  • Start date
  • #1
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Homework Statement


I am trying to find a damping ratio. I know ##k=50## lb##_f##/in, ##m=50## lb, ##c = 0.75## lb##_f##-sec/in.

Homework Equations


##1## lb##_f##/in = ##175.1268## N/m
##1## lb = ##0.4536## kg

The Attempt at a Solution


Then ##k = 8756.34## N/m, ##c = 131.345## N/m-sec, and ##m = 22.675## kg.
$$
\zeta = \frac{c}{2\omega_nm} = \frac{131.345}{2(0.00259)(22.675)} = 1000.26
$$
but this seems awfully large. Are my conversion factors incorrect?
 

Answers and Replies

  • #2
vela
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How is ##\omega_n## defined?
 
  • #3
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How is ##\omega_n## defined?
Thanks. I divided m by k instead of the other way around.
 

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