Pendulum Definition and 1000 Threads

  1. Rafums

    How to calculate acceleration of blobs in any degree pendulum?

    I want to create a method to calculate acceleration of blobs in any degree pendulum (double, triple and more). I have this equation but I am not sure if it is correct, or how to extract acceleration from it. [Mentor Note -- this is a new thread start to correct errors in the previous 2 thread...
  2. brotherbobby

    Pendulum hung from the ceiling of a train

    (a) No, a person seated inside the train compartment will not be able to tell whether the train is accelerating on a horizontal track or moving uniformly up an inclined track by observing the plumb line. (b) I am assuming that both observers are not allowed to look "out" of the boundaries of...
  3. A

    Conical Pendulum with varying string length

    Consider a conical pendulum like that shown in the figure. A ball of mass, m, attached to a string of length, L, is rotating in a circle of radius, r, with angular velocity, ω. The faster we spin the ball (i.e., the greater the ω), the greater the angle, θ, will be, and thus, the smaller the...
  4. yucheng

    Component forces of a pendulum

    I refer to the website below (for more information): http://www1.lasalle.edu/~blum/p106wks/pl106_Pendulum.htm#:~:text=The forces acting on the,the tension of the string.&text=The net radial force leads,is v2/r.) P.S. I'll insert my specific questions in the following paragraphs in this format...
  5. bieon

    Pendulum, Rotational Inertia and Center of mass

    This is the figure given. My Attempt ##T=2\pi \sqrt\frac {I}{0.5gd}## ##\frac {m_r} {l} ## ##dm= \frac {m} {l}dx## ##dI = dm_r x^2## ##dI=(\frac {m_r} {l}dx)x^2## ##I= \int_l^0 (\frac {m_r} {l}dx)x^2 \, dx ## ##I_c.m=\frac {m_r l^2}{3}## ##I_,, = \frac {m_r l^2}{3}+m_p x^2## Given...
  6. Daniel Boy

    Motion Equations by Newton's Formalism for a Double Pendulum

    By Lagrange's formalism, the motion equations for double pendulum are: Using Newton's formalism I can't obtain the second equation. Anyone can help?
  7. PaBlo14101066

    Lagrangian function of a double undamped pendulum

    I must find the Lagrangian for an undamped pendulum using the diagram showed below, I've no idea what to do with the second angle φ2 because is measured from the line that joins the two pivot points. The ecuations I must obtain are as follows I get so many different things but I can't reach...
  8. H

    Plane pendulum: Lagrangian, Hamiltonian and energy conservation

    Hello! I need some help with this problem. I've solved most of it, but I need some help with the Hamiltonian. I will run through the problem as I've solved it, but it's the Hamiltonian at the end that gives me trouble. To find the Lagrangian, start by finding the x- and y-positions of the...
  9. A

    Exploring the Relationship Between Amplitude and Time in a Pendulum Clock

    Hello! So we are given this very interesting physics question, that we should only discuss and not do any calculations. So for a) I've though this if the clock is running too fast,the way to adjust this would be to lengthen the pendelum length,my logic behind this the longer the pendelum the...
  10. aatari

    Finding the Uncertainty in the motion of a pendulum

    Hi guys can someone look at my work for uncertainty and let me know if it makes sense.
  11. F

    Equation Demonstration -- Simple Pendulum Analysis

    I've just studied simple pendulum: The simple pendulum (for small oscillations) differential equation is first image. I've no problem to arrive this result and formula. My problem is to get to the second formula by passing through another formula (Image 3) that my book mentions. I can't...
  12. LCSphysicist

    Find the Lagrangian of a pendulum plane

    Pendulum plane, which suspension executes a horizontal harmonic motion $$x = acos(\gamma t)$$ Position P, orientation x to right and y points below, phi is the pendulum's angle wrt y. $$P = (acos(\gamma t) + lsin(\phi(t)), lcos(\phi(t)) )$$ So executing all that is necessary, i found it...
  13. I

    Period of a Pendulum on the Moon

    The equation that governs the period of a pendulum’s swinging. T=2π√L/g Where T is the period, L is the length of the pendulum and g is a constant, equal to 9.8 m/s2. The symbol g is a measure of the strength of Earth’s gravity, and has a different value on other planets and moons. On our...
  14. T

    Lagrangian mechanics, system of a spring and a pendulum

    Hello! I have some problem getting the correct answer for (b). My FBD: For part (a) my lagrangian is $$L=T-V\iff L=\frac{1}{2}m(b\dot{\theta})^2+mg(b-b\cos\theta)-\frac{1}{2}k\boldsymbol{x}^2,\ where\ \boldsymbol{x}=\sqrt{(1.25b-b)^2+(b\sin\theta)^2}-(1.25b-0.25b)$$ Hence my equation of...
  15. archaic

    Solving a Pendulum Problem with Exponential Solution

    a) This looks somewhat like a pendulum problem (length ##\ell/2##). I reasoned there will be a clockwise rotation, and that the acceleration is due to the force of...
  16. badluckmath

    A simple pendulum is suspended from the ceiling of an accelerating car

    Here is an image of the problem: The problem consist in finding the moviment equation for the pendulum using Lagrangian and Hamiltonian equations. I managed to get the equations , which are shown insed the blue box: Using the hamilton equations, i finally got that the equilibrium angle...
  17. badluckmath

    A simple pendulum is suspended from the ceiling of an accelerating car

    Here is an image of the problem: The problem consist in finding the moviment equation for the pendulum using Lagrangian and Hamiltonian equations. I managed to get the equations , which are shown insed the blue box: Using the hamilton equations, i finally got that the equilibrium angle...
  18. Justinboln

    Calculate the New Velocity and the Velocity of a Pendulum Mass

    Question 1: A pendulum 2.2m long has a mass of 8.5kg suspended from it. The pendulum is initially in a vertical position and is moved to new position 35 degrees from the vertical. (a) How much work is required to move the pendulum to its new position? (b) If the pendulum swings from this...
  19. BayMax

    Double pendulum equations of motion using Newton's laws

    I need help to understand this problem taken from Mechanical Vibrations by S. Rao I know that the equations of motion could be obtained in various ways, for example using the Lagrangian, but, at the moment, I am interested in understanding the method he used. In particular, if I'm not...
  20. LCSphysicist

    Oscillations with fluid and pendulum

    That's a good question, i am not sure how the water in liquid state will influence in the motion, but i imagine that can not exert any torque, i would say in the first case: Hollow sphere inertia moment: 2mr²/3 + ml² (2mr²/3 + ml²)θ'' = -mglθ (1) In the second case, otherwise, we will have...
  21. LCSphysicist

    Simple pendulum subject to a driven force

    The problem is how to construct the right diagram of forces actually Unfortunately, the Fo*cos acting on the ball will not carry the g/l of the solution -mg*sin(´p) + (-bv) + (Fo*cos(wt)*cos(p)) = mx'' Fo*cos(wt) = mx'' + mg*x/l + bv
  22. N

    T-Shaped Pendulum: Find the Total Mechanical Energy

    My answer to part A is correct but for Part B I got an incorrect answer of 0.204J. My working out is sent as an attachment. Part A: Part B: Part C:
  23. anuttarasammyak

    Energy transfer and conservation cases for pendulum motion and EM wave

    Let me ask a very primitive question. To and fro motion of pendulum under gravity tells us potential energy + kinetic energy = const. At the top points potential energy: max kinetic energy :0 At the bottom point potential energy: 0 kinetic energy :max EM wave is usually illustrated as...
  24. jjson775

    How can I accurately calculate the quantum number of a pendulum?

    Summary:: Calculate the quantum number of a pendulum I want to calculate the quantum number of pendulum. L = 1m, m = 1 kg., A= 3cm. I get a period of 2.01 sec. and f = 1/T = .498 sec. E =nhf gives me 2.67x10^31. The correct answer is 1.33x10^31, Where am I going wrong? [Thread moved from...
  25. DerbisEternal

    How do I proceed with two different trig functions containing x on the left?

    Given the total angles in the x direction, I set up this: (mg/cos(x))*sin(x)-Fe=0 then isolated for x: mgtan(x)=(kq^2)/(2*sin^2x) sin^2(x)*tan(x)=(kq^2)/(2mg) From here I am stuck. How do I go forward when x is contained in two different trig functions on the left?
  26. LCSphysicist

    Find the period of a pendulum consisting of a disk of mass M

    I did the first step pretty well, and the answers match, but i don't understand why in the second case the period changes.
  27. D

    How Does a Variable Mass Affect a Simple Pendulum?

    Hello, I've got to rationally analice the form of the solutions for the equations of motion of a simple pendulum with a varying mass hanging from its thread of length ##l## (being this length constant). I approached this with lagrangian mechanics, asumming the positive ##y## direction is...
  28. D

    Phase space of a harmonic oscillator and a pendulum

    Hello everybody, new here. Sorry in advance if I didn't follow a specific guideline to ask this. Anyways, I've got as a homework assignment two cannonical transformations (q,p)-->(Q,P). I have to obtain the hamiltonian of a harmonic oscillator, and then the new coordinates and the hamiltonian...
  29. LCSphysicist

    Period of Pendulum: Spinning Disk Forces & Inertia Moment\

    If the bottom disk is free to spin, will it necessarily spin? all the forces in this disk don't produce a torque. I don't know why we disregard it's inertia moment when it is free to spin (It's intuitively set, but I can't see it mathematically) :\
  30. LCSphysicist

    Two-Disk Pendulum Oscillation: Find Period w/ Mass M & Radius R

    "A pendulum is made of two disks each of mass M and radius R separated by a massless rod. One of the disks is pivoted through its center by a small pin. The disks hang in the same plane and their centers are a distance I apart. Find the period for small oscillation" I don't understand why we...
  31. SilverSoldier

    Differential Equation for a Pendulum

    Suppose we displace the pendulum bob ##A## an angle ##\theta_0## initially, and let go. This is equivalent to giving it an initial horizontal displacement of ##X## and an initial vertical displacement of ##Y##. Let ##Y## initially be a negative number, and ##X## initially be positive. I observe...
  32. aligator11

    Engineering Homework problem - Pendulum oscillatory system

    Hi All, Anyone willing to help out in explaining what eigenfreuqncy for this oscilatory system, would be? Also if anybody knows the equation to calulate this stuff please, if you're willing to share I'd be greatful! Thanks, regards.
  33. brotherbobby

    Work done on a conical pendulum

    The diagram for the problem is shown alongside. In the vertical (##\hat z##) direction we have ##T \cos \theta = mg##. In the plane of the pendulum, if we take the pendulum bob at the left extreme end as shown in the diagram, we have ##T \sin \theta = \frac{mv^2}{r}## (the ##\hat x## axis of...
  34. PickyBiker

    Understanding Force vs Speed for Arduino-Based Inverted Pendulum on Cart

    I am using the Stanford “Dynamics: Inverted pendulum on a cart” document, https://web.stanford.edu/class/me161/documents/InvertedPendulumOnCartSolution.pdf, as the basis for the Arduino c code. I need help with the term Fc (Feedback force on the cart A) because the motor I’m using is a stepper...
  35. Z

    Confused about how to find the mean of uncertainties for pendulum exp.

    I'm confused about how to find the final value of g and its uncertainty. I've done a bit of research and I have encountered conflicting information, some say you have to weight the measurements, some say you have to find the standard deviation then divide by two, etc. I have the following...
  36. Saptarshi Sarkar

    EOM of simple pendulum submerged in a fluid

    The question :- My attempt :- The confusion that I am having is that to get the required form of the equation of motion, I had to approximate ##\theta## to be small to get ##x=l\theta## so that I could get the acceleration and the velocity. But, I had to leave the ##sin(\theta)## in the...
  37. VVS2000

    Compound pendulum experiment to find the acceleration due to gravity

    In this experiment, I still can't figure out why the graph between time period and distance from point of oscillation is like that. Why does it first decrease and increase so steeply? I got the second part because it goes near the centre of gravity and time period becomes almost infinite there...
  38. Saptarshi Sarkar

    Order of anharmonicity of a simple pendulum

    I know that the potential of a simple pendulum is given by the above formula and that we can expand ##cos\theta## to get ##V=mgl\left(\frac{\theta^2}{2}-\frac{\theta^4}{24}+...\right )## I am guessing that the answer is ##\theta^4##, but I am not sure what "order" means here.
  39. Saptarshi Sarkar

    Why is the Coefficient of cosθ Negative in the Exact Pendulum Solution?

    The question is My attempt is given below I am not sure what to do now. I don't understand how I can make the coefficient of ##cos\theta## negative.
  40. B

    Is 51 micro joules the maximum kinetic energy of this pendulum?

    So I have been given a question here which asks me to work out the maximum kinetic energy of the pendulum It has given info such as time period and amplitude, which I had then made use of these formulas Does a kinetic energy of approx 50.98 micro joules seem right here? Any help would be...
  41. Kaushik

    B Forced Oscillations: Pendulum 1 Driving Neighboring Pendulum

    Consider the following setup: In this, let us set the pendulum 1 into motion. The energy gets transferred through the connecting rod and the other pendulum starts oscillating due to the driving force provided by the oscillating pendulum 1. Isn't it? So the neighbouring pendulum starts...
  42. S

    Conical Pendulum: Solving the Height Issue

    So in this instance height is longer than the 3m string which is impossible. Do we just say that when ever H>L, H=L?
  43. Curious_Student

    Mechanics Lab | A Simple Pendulum & a Small Magnet Underneath

    I have measurements of period time and distances that's all: T (sec) D (m) 0.9 0.008 0.91 0.009 0.97 0.01 0.98 0.011 1.06 0.012 I thought about adding the magnetic force like: T=2π*√l/(g+x) but have no clue how to integrate the distance there, I don't know even how to start...
  44. J

    Motion of 2 masses connected by a rod to a pendulum

    I am not sure which other forces I should consider besides those 3. I cannot consider tensions due to the massless rod on the masses since those will not add up to zero.
  45. rzyn

    Rotation and effective gravity on Earth

    I'm interested in calculating effective gravity for a point-mass in a spinning gyro or swinging pendulum bob on a rotating planet undergoing any translational velocities and/or accelerations. I want to investigate the theoretical effects of high-energy mechanical oscillation on orbital...
  46. Prabs3257

    Change in the time period of a pendulum

    I tried taking log and then diffrentiate the standard equation for time period of a pendulum but i am not getting the correct answer
  47. JD_PM

    Equation of motion of a simple pendulum

    The equation of motion of a simple pendulum is: $$\ddot \theta + \frac{g}{l} \theta = 0$$ Our Physics professor told us: 'If you want to become a good Physicist you have to be able to analytically check your answers to see whether they make sense'. In class he took the limits of constant...
  48. JD_PM

    Man rotating in a merry-go-round and grabbing a pendulum

    Where: 1) ##A## is the translational acceleration, ##\Omega## the angular velocity and ##\dot \Omega## the angular acceleration (all relative to the inertial frame attached to the ground ##F##). 2) ##r'##, ##v'## and ##a'## are the position, velocity and acceleration vectors, all relative to...
  49. Q

    Coupled pendulum with external force?

    I got this picture from a superconducting parametric amplifier text I was reading. (The picture is a mechanical analog of a non-degenerate parametric amplifier.) If the balls(red and blue) were oscillating at their own natural frequencies, and an external force is driven(purple), how would the...
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