# Tagged Questions

The tag has no usage guidance.

125 views

### Why do trees sway?

Resonance can also occur in three dimensions (such as wind induced swaying) I tried to make a free body diagram (I know it is terribly wrong) to find the forces that causes the tree to undergo ...
320 views

### How much upward force due to ground vibrations does the Earth exert on you?

Say you're walking by the highway and you can feel the vibrations of cars moving along. How would you approximate the force that the ground is exerting on your feet due to these vibrations?
44 views

### SHM with acceleration at mean position

Suppose we have an equation of motion as $$\frac{d^2x}{dt^2} = -kx + c,$$ then can it be called a SHM? Since acceleration is still proportional to displacement. But then, how will we define the mean ...
42 views

### phase difference of two reflected wave

Suppose a tuning fork generates sound waves with a frequency of 100 Hz. The waves travel in opposite directions along a hallway, are reflected by end walls, and return. The hallway is 47.0 m long and ...
48 views

### Free body diagram when forces are not directly in contact with the object

I was trying to use Newton's second law to describe the motion of the following pendulum: However, I was confused as to how to include the spring in Newton's second law. I was able to set up a ...
49 views

### Damped sinusoidal motion with initial velocity or acceleration [closed]

I am looking for the equation of damped sinusoidal motion with an initial velocity. For example: a mass is moving by spring1 force. At ...
67 views

### Damped Pendulum (generalised)

I know the differential equation for the swinging of a simple pendulum: $\displaystyle\frac{\partial^2\theta}{\partial t^2} + \left(\frac{g}{L}\right)\sin\theta = 0$ where: $L$ is the length of ...
207 views

### Eigenvalue physical meaning [closed]

What is the physical significance of eigenvalues or eigenvectors?? Please try to explain in very simple language simple harmonic oscillator , potential well could you support your answer by ...
43 views

18 views

### Diagonal patterns in a Chladni plate experiment [duplicate]

I am an undergraduate student that's taking physics classes and have been assigned a seminar concerning Chladni figures. I understand the theory behind it, the standing waves in 1D and 2D, Bessel ...
58 views

### What is the source of the discrepancy in my period-amplitude graph?

I was taught at school that the formula for period of a pendulum is $T=2\pi \sqrt{\frac{l}{g}}$ Later I found out that this is only an approximation valid for small angles and the accuracy of this ...
47 views

### Oscillating block amplitude change when 2nd mass added [closed]

There is a oscillating block with amplitude $A$ and mass $M$. We add a mass $m$ with zero velocity and vertically.when the block is in this two conditions: ...
90 views

### How can a harmonica make some different sounds?

My first post: I have found an interesting harmonica here. So, I tried to know more about harmonica. And, I have read this article , in which the author doesn't mention the physical calculation, ...
187 views

### In an RLC series circuit on resonance, how can the voltages over the capacitor and the inductor be larger than the source voltage?

Consider an RLC circuit in series, of the form If the source drives the circuit in AC at the resonance frequency $\omega =1/\sqrt{LC}$, the peak-to-peak voltages on the capacitor and the inductor, ...
18 views

### Why are sinusoidal waves so natural? [duplicate]

My question is, why do very simple systems like a spring with a mass attached to it, or an LC oscillator, or a string, all vibrate or oscillate with a sine wave? I fail to see the "circle" or the "...
29 views

### For series LCR oscillations (resonance), why does current have to be maximum?

I learned about a year back that systems will go into oscillations with high amplitudes if the frequency of the forced oscillations coincide with the natural frequency of the system leading to ...
48 views

### Prove that $n$ degrees of freedom leads to $n$ normal modes

I have probably missed that during my studies. I intuitively know (but then I might be wrong in some detail, that's why I am asking), that $n$ degrees of freedom in oscillating system leads to $n$ ...
88 views

### Total energy of a simple pendulum proportional to the square of the amplitude? [duplicate]

It is known that in simple harmonic motion, the total energy of the system is proportional the square of the amplitude, but how can I prove that for a simple pendulum where amplitude is the arc length ...
103 views

### Magnitude of tension in a bent string

I understand tension in a straight string as a reaction force to a weight, which acts along the string, ultimately resulting from the attractive forces between the constituent particles of the string. ...
44 views

### How to explain the motion of these pendulums? [duplicate]

Got very interested recently in a video I saw running thru my feed: https://www.facebook.com/PortalAECweb/videos/913996365374257/ Well, I got very intrigued about the physics of it and wanted to ...
173 views

### Simple harmonic motion versus oscillations

I want to see whether certain oscillations in my daily life, such as the oscillation of violin strings when plucked, are simple harmonic motion or not. Can we identify whether an oscillation is simple ...
181 views

### Why is the energy stored in a driven oscillator equal to the product of friction dissipated power $P_\text{fr}$ & decay time $\tau$ at resonance?

This is an excerpt from Waves by Frank S Crawford Jr. [...] At steady-state the time-averaged power must equal the time-average of power dissipated by friction. The instantaneous frictional force ...
84 views

### Motion of string fixed at both ends

I was reading about the Fourier analysis from Waves by Frank S Crawford Jr. But I got trapped at the very beginning; this is the excerpt that troubled me: Motion of string fixed at both ends. ...
30 views

### What is the role of the hyperfine interaction in singlet-triplet transition of spin correlated radical pairs?

I don't really understand the hyperfine structure. I understand, that the magnetic dipole moment of the nucleus interacts with the spin of an electron, causing a split between the energy levels of ...
112 views

### An overdamped oscillator with natural frequency Ï‰ and damping coefficient Î³ starts out at position x0 > 0 [closed]

An overdamped oscillator with natural frequency Ï‰ and damping coefficient Î³ starts out at position x0 > 0. What is the maximum initial speed (directed toward the origin) it can have and not cross the ...
266 views

### Can friction change the resonance frequency of a system?

I am simulating the transient response of a mass-spring-damping system with friction. The excitation is given in the form of a base acceleration. What I am not sure about is: can the friction change ...
25 views

### How to determine time of dephasing?

Let's assume that I have an oscillating value A. After some time the oscillations are being damped so the diagram of A is like on the picture below: Now how to determine when does the A is reduced ...
59 views

### Energy of driven dampened oscillator

Given the oscillator described by: $$m\ddot{x}+\gamma \dot{x}+kx=F_0\cos(\omega t)$$ And supposing the system is at it's stable state, I wish to calculate the following: 1) The system's energy at any ...