Phase Space Momentum Position Graphs of Two Harmonic Oscillators
Consider two independent harmonic oscillators of identical mass oscillating about the origin with angular frequencies ω1 and ω2, having total energies E1 and E2, respectively. The variation of their momentum p with position x is depicted in the figures. If ba=n2 and Ra=n, then the correct relation(s) is(are)
For a simple harmonic oscillator of mass m, displacement x, and momentum p, the total mechanical energy E is given by the sum of kinetic and potential energies:
E=2mp2+21mω2x2
Rearranging this into the standard equation of an ellipse in the phase space (x,p):
(mω22E)2x2+(2mE)2p2=1
From the given phase space diagrams:
Oscillator 1:
The phase space trajectory is an ellipse with semi-major axis a along the x-axis and semi-minor axis b along the p-axis.
a=mω122E1b=2mE1
Taking the ratio of a to b:
ba=2mE1mω122E1=mω11
Given that ba=n2, we get:
mω11=n2⟹mω1=n21— (1)
Oscillator 2:
The phase space trajectory is a circle of radius R. Thus, the semi-axes along x and p are both equal to R:
R=mω222E2=2mE2
Equating the two expressions for R:
mω222E2=2mE2⟹mω2=1— (2)
Step 1: Ratio of Angular Frequencies (ω1ω2)
Using equations (1) and (2):
ω1ω2=mω1mω2=1/n21=n2
This confirms that Option (B) is correct.
Step 2: Relation between Energy and Angular Frequency
From the expression for b and R:
E1=2mb2andE2=2mR2
Now, let's compute the ratio ω1E1:
ω1E1=ω1b2/(2m)=2(mω1)b2
Substituting mω1=n21 into the expression:
ω1E1=2b2n2
We are given the relations:
ba=n2⟹b=n2a
Ra=n⟹a=nR
Substituting a=nR into b=n2a:
b=n2nR=nR⟹bn=R
Substituting bn=R back into the expression for ω1E1:
ω1E1=2(bn)2=2R2