Amount of time for a half period to occur

  • Thread starter Capncanada
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  • #1
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Homework Statement



A mass-spring system has k = 105 N/m and m = 1.75 kg.

If it is undergoing simple harmonic motion, how much time does it take the mass to go from x = A to x = 0?

Homework Equations



T=2pi*sqrt(m/k)

The Attempt at a Solution



Tried plugging in the values for the equation I gave to find T, then cutting it in half to find the amount of time the question asked for, but it's not the correct answer.
 

Answers and Replies

  • #2
vela
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What exactly is one cycle? If you understand that, you'll see why your answer is wrong. It may help to look at a diagram that shows one period in your textbook.
 
  • #3
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When the mass goes into the spring and back?
 
  • #4
ehild
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Sketch the x(t) function for a full period and see.

ehild
 
  • #5
vela
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When the mass goes into the spring and back?
Yes. So in one cycle, if it starts at x(0)=A, it ends at x(T)=A, but more important, what does x(t) do in between? As ehild suggested, plot x(t) for one cycle.
 
  • #6
dextercioby
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Who's A and can you link it to T ? EDIT: So A's the amplitude...
 
Last edited:
  • #7
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Uhh x goes to A? Which equation can I use to solve for that? x=Acos(ωt)?

Sorry I'm braindead been studying all morning I just want this homework done.
 
  • #8
ehild
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Which equation can I use to solve for that? x=Acos(ωt)?

Yes. x = A cos (2pi* t/T). How does it look like? What is x at t=0, t=T/8, T/4, ...

ehild
 
  • #9
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So I can plug in x as A so that A cancels out here and then solve for t where T = 1/2?
 
  • #10
ehild
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So I can plug in x as A so that A cancels out here and then solve for t where T = 1/2?

Is T=1/2???????


Would you please show me a cosine function? Please!!!!

ehild
 

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