Springs & Energy

[Quantum Fizzics]

Homework Statement

Hello, I'm having an issue with a question I have all the numbers and everything but I can't 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 I am just stuck at part a) I really do not know how start please help thanks

 

[haruspex]

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?

 

[Maged Saeed]

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 ??

 

[haruspex]

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.