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mkerikss
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Homework Statement
A particle with with the mass of m is attached to a spring (with no mass, spring constant k, length l) which is attached to a wall. The particle is moving with no friction along the x-axis.
a) Write the particles motion equation, and find the general solution to the motion using a test-method.
b) Using the solution, determine which are the classic turning points.
c)What is the work done by the spring-force from x0 to x, and show that the force is conservative. Write the spring-force' potential energy U's expression.
d) I have solved it and it isn't needed anymore.
e)Write the harmonic oscillator's principle of conservation of energy.
f)Show usin the solution to a), that the particle's total energy is constant. What is the constant.
g)Write the general solution to the motion equation for a harmonic oscillator from the principle of conservation of energy.
Integrate: [tex]\int((a+bx+cx2)-1/2)[/tex]=-(-c)-1/2arcsin((2cx+b)/\sqrt{b2-4ac} , c<0, b2-4ac>0
(I have no idea what this question's all about so I may very well have translated it incorrectly)
h) Determine the total energy in g) and use it in f)
i) Determine the total energy in e) using the principle of conservation's classic turning points. Did you get the same result as in b). Hint: The mechanical energy\geq0
Homework Equations
The Attempt at a Solution
NII gives -kx=ma
Eq.1: d2x/dt2+kx/m=0
I used x(t)=Asin(rt+\theta)
x''(t)=Ar2(-sin(rt+[tex]\theta[/tex]))
I put these into eq.1 and got r=(n[tex]\pi[/tex]-[tex]\theta[/tex]/t and r=[tex]\sqrt{k/m}[/tex]
I don't really know what to do with the first answer, but the second gives me the answer we're supposed to get.
Eq.2: x(t)=Asin(\omegat+\theta)
b) Not sure about this one, as I'm unsure what theses points are, but someone told me that they are the points when the amplitude +-A. Is this correct?
c)W=\intF*ds=-kx2/2+kx_{0}2/2 (the integrat is from x_{}0 to x)
W(x0 to x)=U(x0)-U(x)
U(x)=-W(x0 to x)=kx2/2-kx_{0}2/2=kx2/2
because U(x0)=0, and x0=0
d)I have solved it and I don't need it in the rest of the problem so I won't write it here.
e)E=mx2/2+kx2/2
The second term is the potential energy, but I don't know where the first term comes from. It must be the mechanical energy but why does it look like that?
f) I have tried to put Eq.2 into the equation above (in e)) to get a constant but that doesn't work, and now I don't know what to do. Help me please!
g,h,i) I really don't have any idea how to solve these.
Edit: Why does this text look sp weird. I hate computers