A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force acting on the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also to a slight degree on the amplitude, the width of the pendulum's swing.
From the first scientific investigations of the pendulum around 1602 by Galileo Galilei, the regular motion of pendulums was used for timekeeping, and was the world's most accurate timekeeping technology until the 1930s. The pendulum clock invented by Christiaan Huygens in 1658 became the world's standard timekeeper, used in homes and offices for 270 years, and achieved accuracy of about one second per year before it was superseded as a time standard by the quartz clock in the 1930s. Pendulums are also used in scientific instruments such as accelerometers and seismometers. Historically they were used as gravimeters to measure the acceleration of gravity in geo-physical surveys, and even as a standard of length. The word "pendulum" is new Latin, from the Latin pendulus, meaning 'hanging'.
Homework Statement
A perfectly elastic spring swings in a vertical plane as a simple pendulum with a mass m suspended at the bottom of the spring. The force constant for this spring is ##k## and the unstretched length is ##L##. The spring is carefully held in the horizontal position so that the...
Homework Statement
Homework EquationsThe Attempt at a Solution
Time period of a simple pendulum is given by 2π√(L/g) .
By uniform mass distribution , I am assuming density of mass of bob to be constant .
I don't understand how time period depends on the mass of the bob of a simple pendulum .
1. The problem statement, all variables and gihttps://www.physicsforums.com/attachments/218400 ven/known data
Assuming the string from a simple pendulum did not have negligible mass and the pendulum bob was not a point mass, then determine an expression for the period of a single small-amplitude...
Homework Statement
I'm trying to solve problem a problem of complete energy of doubled pendulum (2 mathematical pendulums connected by a string).
For a kinetic energy I would get (1/2) J(w_1)ˆ2 + (1/2) J(w_2)ˆ2 and for a potential energy of a spring (1/2) k (ϕ_1-ϕ_1)
What about gravitational...
Hi everyone. I just have a very quick question regarding position time graphs and velocity time graphs for a pendulum.
As we know, at the maximum displacement, the acceleration is at its maximum and the velocity is zero, and vice versa when the displacement is zero.
When we put this...
Homework Statement
A pendulum having a bob of mass ##m## is hanging in a ship sailing along the equator from east to west. If the ship sails at speed v what is the tension in the string?. Angular speed of Earth's rotation is ## \omega ## and radius of the Earth is ## R ##
Homework Equations...
Assume a pendulum was swinging in a lift. If the cable breaks and the lift starts to accelerate down at g would the pendulum stop swinging and freeze in its current position?
Merry Xmas.
G.
Homework Statement
A solid sphere is cut in half and a homogeneous hemisphere of radius r and mass M is set upon a table(with its flat side up). The surface of the table is perfectly rough. The hemisphere rocks back and forth with small amplitude excursions from equilibrium. What is the length...
Homework Statement
Homework EquationsThe Attempt at a Solution
Trying to answer it before solving it,
The maximum tension force is mg, so the average has to be less than this. Hence, the option (a) and (c) are not correct.
## T = mg \cos \theta ##, where ## \theta ## is the angle between...
Homework Statement
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A solid sphere of mass M and radius R is suspended from a thin rod. The sphere can swing back and forth at the bottom of the rod. Find an expression for the frequency of small angle oscillations.Homework Equations
f = 1/2(pi) sqrt(MgR/I)
I for a solid sphere 2/5MR^2The...
Imagine we are all cavemen without satellite technology and just discovered the Foucault pendulum! As we know the angle of presession depends on the latitude. This can be used to prove that the Earth is rotating, right? Now by putting several Foucault pendula around the Earth, at equidistant...
Homework Statement
I have the answer for part a, which is:
$$\theta '' + \frac{a}{r} \cos \theta + \frac{g}{r} \sin \theta$$
My issue lies with getting the following equation of motion for part b,
$$\theta '' + \frac{g}{r} \cos \alpha \sin \theta = 0$$
Homework EquationsThe Attempt at a...
So I'm doing a lab in class, and when I graphed the Period vs Length of the string, I got it in the form $T=A\sqrt{L}$, but I don't really know what the value $A$ represents nor what its unit is... Can someone help me?
Hey! :o
I am looking at the following:
Find the energy function for the double pendulum, with vertical constant and uniform gravity field
for motion restricted at vertical plane
for motion in space
We have that the energy function is the sum of the potential and the kinetic energy...
Homework Statement
The differential equation of motion for the simple pendulum can be shown to be
##\ddot {θ} = -(g/L)sinθ##. Given that L=9.81 m and that the pendulum is released
from rest at θ=60deg, determine the time required for the pendulum to reach the position
θ=0deg. Use Δt=0.10s, and...
Homework Statement
A 10g ball is fired at 6 m/s into a 280g pendulum. What maximum angle will the pendulum swing to if the effective radius of the pendulum is 28cm?
Homework Equations
How to find theta?
The Attempt at a Solution
I converted 28cm to 0.28m; 10g to 0.010kg; and 280g to 0.280kg...
Homework Statement
Imagine a number line -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5
A pendulum begins at -1 and then swings towards the LEFT or RIGHT. There is no knowing how fast the pendulum is traveling or how much energy it has but will only swing LEFT or RIGHT.
(I) Need to work out the...
So, I'm really bothered with something. Let's suppose there's a simple pendulum with a rigid sphere on it's end. In order to get the motion equations I thought we could use two approaches. One would be using rigid body dynamics (torque, moment of inertia ...), the other one would be using...
When doing a problem on a pendulum undergoing elliptical motion, I came across sn(z), which is apparently a "Jacobi Elliptic Function". When I looked into it further, I saw that these functions are essentially circular trigonometric functions but about an ellipse instead of a perfect circle. Can...
Hi , please i want to know if i have flat plate (rectangle) but its fixed like pendulum (fixed from one end and free at the other end and can rotate around this fixed end) i want to know the drag force due to air on this plate?
Homework Statement
13.54 The pentulum is released from rest with θ = 30deg. (a) Derive the equation of motion
using θ as the independent variable. (b) Determine the speed of the bob as a function of θ.
The solutions given in the textbok are a) ##\ddot θ = -4.905sinθ rad/s^2##
b) ##6.26\sqrt...
Homework Statement
13.53 The tension in the sting of the simple pendulum is 7.5N when θ=30deg.
Calculate the angular velocity and angular acceleration of the string at this instant.
Homework EquationsThe Attempt at a Solution
Is this correct?
Homework Statement
There's a pendulum with mass m and longitude L strapped to a disk with radius R that rotates with an angular velocity ω. Calculate the angle that the pendulum is shifted (Φ) depending on ω.
You are given m, L, R, ω, g. Calculate Φ depending on ω.
Little drawing (with my...
Well, this might be the stupidest question ever, but whatever. I was just thinking about a problem where a pendulum is attached to something that spins around itself (image below) and thought that maybe Centripetal Force might be a projection of tension on a vector that is perpendicular to ω...
<Moderator's note: Moved from a technical forum and therefore no template.>
A simple pendulum of length l (supported by a light, rigid rod) is released from rest at a small angle to the upward vertical.
Show that the time taken for the angular displacement to increase by a factor of 10 is...
Homework Statement
For calculating angular frequency of a physical pendulum, I consider its center of mass motion.
The COM motion is a simple pendulum motion.
Considering a coordinate system whose origin is the pivot point. Then, the COM is the length of the corresponding simple pendulum. Is...
Hello! I hope someone could help me to solve mu doubt, I am very confused and I don't find answers in internet. My question is about pendulums. I know the angular frecuency of a pendulum is give by the equation w= sqrt(g/L). But also i know the angular velocity (also named with "omega") can be...
I have a rigid body pendulum that is used to strike an object at the bottom of its swing. Ultimately I would like to know how much forced is the object being struck with. Could I do this with just knowing the velocity of the weight? I was thinking then I could get P=MV. Can someone please help e...
I'm having no problem finding the maximum speed of a pendulum but I'm not sure when I move its start point and measure point.
I would like to know the speed of a pendulum at 30 degrees that has been dropped at 140 Degrees. I'm just giving some numbers to explain that it is above the horizontal...
If a pendulum swings in a given arc, because of gravity acting on it in the vertical direction, does the linear and angular momentums change since it is picking up velocity because of gravity?
I got stucked with a solution of a problem.
I have a pendulum of r radius which is in G gravitational field. So the working acceleration on the bob is a function of the angle. That is Gcosθ.
The mass of the bob = m
The radius of the string of the pendulum = r
Gravitational force is G. So the...
Homework Statement
For number 3,4,5
https://s4.postimg.org/qbp3xzq65/IMG_1092.png
https://s22.postimg.org/u220j60sx/IMG_1093.pngHomework Equations
Centripetal force = m v^2/R
T = centripetal force + w
Sigma F = m.a
The Attempt at a Solution
Number 3. Find the v at D point using...
Okay...The time period of a pendulum is independant of its mass and amplitude.For the "independance of mass",the reason is that, for same amplitude (distance from mean position), any change in mass would have no effect on the acceleration of the mass (gravitational acceleration is...
Hello All,
I was performing an experiment in which the perod of oscllation of a pendulun at different lengths is measured using a light gate.
while performing the experiment i noticed that the string was slightly elastic, differing from the perfect pendulum.
I was attempting to figure...
Hi everyone!
I have few questions which I think might actually be simple, but I would like some confirmation if possible.
Here's the situation:
I am doing a research project for my MSc. in Forensic Anthropology. The goal of my project is to study the marks left on bones by bladed weapons (in...
Homework Statement
This is my 'carrying out a practical investigation' assignment for Maths. I've attached the coursework (what I've wrote up to now) and my main concern is whether I've got the right differential equation to find 3 new velocity values throughout the pendulum trajectory...
I'm studying the motion of a physical pendulum, could someone help me make the final step in figuring out how to find the period so I can make predictions before carrying out a practical? Basically I have a meter rule with holes drilled along the length and will be pivoting it at various points...
Hi, I'm trying to study Runge-Kutta method and apply on a simple pendulum.
Using a timestep dt=0.1 (h=0.1) the pendulum increses energy of 1% every period...
while in this site:
https://www.myphysicslab.com/pendulum/pendulum/pendulum-en.html
decreses energy about 0.01%
What am I doing wrong...
We have a car accelerating at a uniform rate ## a ## and a pendulum of length ## l ## hanging from the ceiling ,inclined at an angle ## \phi ## to the vertical . I need to find ##\omega## for small oscillations. From the Lagrangian and Euler-Lagrange equations, the equation of motion is given...
Homework Statement
Consider a point mass of mass m suspended from an ideal, massless spring. Let ##\theta ## be measured from the vertical. Find the displacement of the mass as a function of time if the spring is initially stretched/compressed a distance ## l_0 ## and has an initial velocity...
Homework Statement
Hi, I have the following question...
A pendulum consisting of a mass of 1kg is suspended from a string of length L. Air resistance causes a damping force of bv where b = 10-3 N/m
1) Derive and solve the equation of motion
2) Calculate the fractional decrease in amplitude...
Homework Statement
Suppose the pendulum string is attached to a point on the ceiling 30 cm from the wall. The weight is moved away from its rest position and released at time t=0. At time t=1.4 sec, it reaches its maximum distance from the wall, 37.4 cm away, and then swings back toward the...
Hi, I've derived the equation of motion for a regular single pendulum, but do not know how to solve the differential equation.
I have the following:
r2θ''2=mg(cosθ-rsinθ)
Hi guys,
I need to transform Newtonian solution of motion equation for spring (elastic) pendulum into Matlab or Microsoft Excel. I want to use Euler´s Method (or Runge Kutta Method) of numerical solution for that problem. I know all the equations but I have a problem with making some code from...
When we have solid rod instead of spring I can solve this problem in Microsoft Excel either with Euler´s method or Runge Kutta method, but that spring makes this problem hard for me.
Hi,
I would like to ask what is the formula for non-harmonic oscillation of pendulum? I know that formula for harmonic oscillation of pendulum is: (d^2 φ)/(dt^2 )+g/r sinφ=0 where φ is angle, t is time, g is gravitational acceleration, r is length of a rope. I know that harmonic oscillation...
Homework Statement
A simple pendulum is formed by a light string of length ##l## and with a small bob ##B## of mass ##m## at one end. The strings hang from a fixed point at another end. The string makes an angle ##\theta## with the vertical at time ##t##. Write down an equation of motion of...
Hello,
I was solving a problem related to Eddie currents recently and I need some help with simulating it numerically. Basically, we have a disc-like copper pendulum entering a region of uniform magnetic flux density B (see diagram). I understand that I need to use Faraday's law:
\nabla...