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Simple Harmonic Motion - Two springs attached

  • Thread starter Koey
  • Start date
  • #1
3
0
Yeah I got this question and I'm just wondering if I'm doing it right.

Homework Statement



A spring normally 10cm long and whose force constant is 150 n/m is connected to another spring normally 20cm long and whose force constant is 100 n/m. The combination is then pulled out so that its ends are 50cm apart.

a) find the amount each spring is stretched.

b) a 400g block on a frictionless surface is attached between the springs. find its period of oscillation.

Homework Equations



T = 2pi sqroot(m/k)
F = kx

The Attempt at a Solution



Well I tried something no idea if it is correct..

a) Made Xtotal = 0.2 because I subtracted the spring lengths
X1 = F/150
X2 = F/100
(F/150)+(F/100) = 0.2
F = 12
Then I subbed F values back into the original 2 equations to get X values.

b) For this question I assumed the combined force constant for the springs would be additive so
k = 250 n/m
m = 0.4 kg

T = 2pi sqroot (m/k)
= 2pi sqroot (0.4/250)
= 0.25s (approx)

Need to know if I'm doing this right or horribly wrong..

Cheers
 

Answers and Replies

  • #2
ehild
Homework Helper
15,477
1,854
It is OK.

ehild
 
  • #3
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Does that means i've done it right??
 
  • #4
ehild
Homework Helper
15,477
1,854
Does that means i've done it right??
YES!!!! :smile:

ehild
 

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