Springs & Energy

  • #1

Homework Statement


Hello, I'm having an issue with a question I have all the numbers and everything but I cant quite get the answer correctly and its very frustrating..

A mass, m is held at UEP of a vertical spring constant k & allowed to fall. Calculate:
a) The maximum stretch(max bottom)
b) The amplitude of vibration


Homework Equations


PEg + PEe + KE= PEg' +PEe'+ KE'
h = xo = mg/k

The Attempt at a Solution


I've solved the amplitude of vibration already im just stuck at part a) I really do not know how start please help thanks
 

Answers and Replies

  • #2
haruspex
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You've quoted the right equations - just fill in the blanks: in terms of the desired unknown, what are the loss in gravitational PE, the gain in spring PE, and the change in KE?
 
  • #3
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about maximum stretch
I'm not sure but I think I think that depends on the spring ,,
If it is in equilibrium after falling we will use the laws of conservation of energy ,
If it is not "say it is oscillating" we shall use newton second law , because in oscillation , we can't specify the final and initial positions of the string [it would go back farther than it's initial position when it's allowed to fall]

I'm I right ??
 
  • #4
haruspex
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about maximum stretch
I'm not sure but I think I think that depends on the spring ,,
If it is in equilibrium after falling we will use the laws of conservation of energy ,
If it is not "say it is oscillating" we shall use newton second law , because in oscillation , we can't specify the final and initial positions of the string [it would go back farther than it's initial position when it's allowed to fall]

I'm I right ??
No, it's not the stretch at equilibrium we want, it's the maximum stretch, and that occurs once in each oscillation.
 

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