What is Simple pendulum: Definition and 199 Discussions

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timekeeper, used in homes and offices for 270 years, and achieved accuracy of about one second per year before it was superseded as a time standard by the quartz clock in the 1930s.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'.

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  1. H

    Simple Pendulum and harmonic motion

    Homework Statement A sim[le pendulum has a mass of .25kg and a length of 1.0m. It is displaced through an angle of 15degrees and then released. What are (a) the maximum speed, (b) the maximum angular acceleration, and (c) the maximum restoring force? Solve the problem once by using the...
  2. B

    Electric Field Problem and simple pendulum

    Homework Statement If you had a simple pendulum of length 1 m and mass 5e-3 kg placed in a uniform electric field E that is directed vertically upward. The bob has charge of -8e-6 C. the period is 1.2 s what are the magnitude and direction of E? First, didn't they already tell us that E...
  3. C

    Using a simple pendulum to determine g

    Using a simple pendulum to determine "g" 1. Using a simple pendulum to determine "g" Basically, we were asked to do an experiment where we measured with a stopwatch for 20 complete oscillations for a pendulum bob swinging through a small arc (10 degrees). We increased the length of the string...
  4. H

    Simple pendulum, det the change of its period?

    Qn. A simple pendulum has a length of 3.00m. Det the change in it period if it is taken from a point where g=9.80ms2 to a higher elevation where the acceleration due to gravity decreases to 9.79ms2. i cannot seem to start the question and a bit unsure here... here is what i get...
  5. M

    Simple pendulum: does the period change in a horizontally accelerating frame

    [SOLVED] Simple pendulum: does the period change in a horizontally accelerating frame Homework Statement Simple pendulum which is 5.0m long. What is its period when it is in a truck accelerating horizontally at 5.0m/s/s? Homework Equations w = sqrt(g/d) w = 2pi/T The Attempt at a...
  6. M

    How Can We Prove the Time Period Formula of a Simple Pendulum?

    Homework Statement As part of my coursework, I need to be able to prove the formula for the time period of a simple pendulum. I know what the formula is but I really don't know how to prove it. I would appreciate any help. Homework Equations T = 2*PI*Root(l/g) The Attempt at a...
  7. T

    Calculating Pendulum Bob Properties: Mass 500g, Length 2m, 10° Displacement

    1. A mass of 500g is used as a pendulum bob so that it forms a pendulum that is 2meters long. The pendulum is displaced from its rest position by an angle of 10 degrees. A. How high is the pendulum bob above its original position? B. What is the magnitude of the energy that the pendulum bob...
  8. S

    Simple Pendulum - Linear Second-Order Equation

    Homework Statement In section 4.7, we discussed the simple pendulum consisting of a mass m suspended by a rod of length l having negligible mass and derived the nonlinear initial value problem. (17) \frac{d^{2}\phi}{dt^{2}} + \frac{g}{l}sin\theta=0 \theta(0) = \alpha \theta'(0) = 0...
  9. S

    What are the unknowns in a simple pendulum problem and how can they be solved?

    Homework Statement A sphere of mass 0,5 kg bounces from 2 extreme positions like a pendulum. When it makes a 25º with vertical the sphere is 20 cm high from equilibrium position and the tension value is 5,5 N. Find: - Total acceleration - Length of the wire - velocity modulus in that...
  10. T

    Simple Pendulum Homework: Amplitude of 25 cm/s Push

    Homework Statement A pendulum consists of a 500 g bob at the end of a massless 75 cm rod. (a) While it is hanging vertically down, the bob is given a push that starts it moving at 25 cm/s. What is the amplitude of the resulting oscillation in degrees? You may neglect damping...
  11. C

    Understanding Simple Pendulum: Solving for Speed in Lowest Position

    The figure shows a simple pendulum of length L = 54 cm and mass m = 2.4 kg. It's bob is observed to have a speed of vo = 4.8 m/s when the cord makes an angle θo = 24°. What is the speed of the bob when it is in its lowest position? I'm having problems with this type of problem, its a new...
  12. B

    Understanding Simple Pendulum Experiment: Water-Filled Sphere Explanation

    This is my first time ever taking a physics class...and needed an explanation. In lab we're doing a simple pendulum experiment. Given the equation T=2pi(sqrt L/g) and noting observations with different pendulum lengths we must then answer this question: A hollow sphere is filled with water...
  13. M

    Understanding the Simple Pendulum: Confusion in Lab and How to Solve It"

    Homework Statement I was wondering if someone could help me with this http://img.photobucket.com/albums/v27/SilverMoonStar/bn.jpg my lab prof doesn't speak english well and left my lab partners and I slightly confused. For the second column we did the average of 70.1 + 69 + 69 and got...
  14. D

    Simple Pendulum Motion and Physical Pendulum

    Homework Statement 1) Find the period of a pendulum 50 cm long when it is suspended in (a) a stationary elevator; (b) an elevator falling at the constant speed of 5.0 m/s; (c) an elevator falling at the constant acceleration of 2.0 m/s2; (d) an elevator rising at the constant speed of 5.0 m/s...
  15. X

    Show that the potential energy of a simple pendulum is proportional

    Homework Statement Show that the potential energy of a simple pendulum is proportional to the square of the angular displacement in the small amplitude limit. Homework Equations U=mgh sin^2wt + cos^2wt=1 The Attempt at a Solution I can't figure out where to start.
  16. T

    Error in Simple Pendulum experiment

    Homework Statement In Physics lab we performed a simple pendulum with an apparatus that involved a cylindrical mass. We measured the period dependence on mass, amplitude, and length. Throughout our experimentation we assumed that the mass used behaved similar to a point mass. After...
  17. maverick280857

    Which is better for measuring g? Bar Pendulum or Simple Pendulum?

    Homework Statement Which is a more accurate way of measuring g, the acceleration due to gravity? Using a bar pendulum or a simple pendulum? Homework Equations Bar Pendulum = metal rod with slotted holes at fixed distances, which serve as pivots. The Attempt at a Solution For...
  18. R

    Solving Tension in Simple Pendulum at Centre Point

    Homework Statement A simple pendulum is oscillating. When it is at the centre, what is the value of tension in string? Homework Equations The tension= The weight= mg The Attempt at a Solution Am i right? Please help!
  19. T

    Simple Harmonic Motion of Inverted Simple Pendulum with a Helium Balloon

    Homework Statement A light balloon filled with helium of density 0.175 kg/m3 is tied to a light string of length L = 3.35 m. The string is tied to the ground, forming an "inverted" simple pendulum (Fig. P13.63a). If the balloon is displaced slightly from equilibrium, as in Figure P13.63b, show...
  20. P

    Among Simple harmonic oscillation, simple pendulum and physical pendulum

    What is the similarity between Simple Harmonic Oscillation(SHO), simple pendulum and a physical pendulum? I never understood it. Like what's the physical significance of SHO, or the energy and momentum change in oscillating motion?
  21. C

    Simple Pendulum Problem this one's kinda tough

    A simple Pendulum is made from a 0.65-m-long string and a small ball attached to its free end. The ball is pulled to one side through a small angle and then released from rest. After the ball is released, how much time elapses before it attains its greatest speed? My Approach: I used this...
  22. F

    Solving for T in a Simple Pendulum: Troubleshooting and Tips

    still reviewing my test and I am having trouble. A pendulum consists of a bob of mass 0.14kg at the end of a light string of length 0.66 meters, whose other end is fixed. the number of oscillations executed by the pendulum each minute is...? so far this is what I've got L= (gT^2) /...
  23. Reshma

    Lagrangian for simple pendulum

    Find the Lagrangian for a simple pendulum of mass m whose point of support moves uniformly on a vertical circle with constant frequency \omega in a uniform gravitational field. Let 'l' be the length of the pendulum string. Using plane polar coordinates: Let T be the KE of the pendulum. T =...
  24. N

    Simple Pendulum lab not so simple

    This lab I would LOVE to use as TP. I'm sure its me being stupid and not really the lab. The problem I have it trying to set up a graph for this. I don't know if I did it right. My numbers seem way off. I'm supposed to make a period^2 vs length graph. Part of what I don't get is if I'm...
  25. J

    A Simple Pendulum: Concentrating Weight on a String or Rod

    Mass and weight! It is said: "A simple pendulum, is a concentration of mass on the end of a string or rod" Instead of using the word mass why don't we use the word "weight"?
  26. L

    Period of a Simple Pendulum in a Moving Truck

    A simple pendulum is 8.00 meters long.(a) What is the period of simple harmonic motion for the pendulum if it is place in a truck that is accelerating horizontally at 2.00 m/s^2There were 2 other questions with accelerating upward and downward in an elevator, and those numbers I either added or...
  27. Amith2006

    Simple pendulum, and inertial and gravitational mass

    Sir, A simple pendulum has a length L. The inertial and gravitational masses of the bob are m1 and m2 respectively. Then the time period of the simple pendulum is given by T = 2(pie)[m1L/m2g]^(1/2) {Read as 2 pie root m one L by m two g) My question is that the...
  28. J

    How Can You Calculate the Original Length of a Simple Pendulum?

    A simple pendulum of unknown length was found to execute 100 oscillations in 375.6s. The length was then reduced by 50,100,150,200 and 250cm, and the corresponding times of 100 oscillations were found to be 347.7, 317.4,283.9, 245.9 and 200.7: find by calculation the original length of the...
  29. Hootenanny

    Deriving the Time Period Equation for a Simple Pendulum

    I am attempting to derrive the equation for the time period of a simple pendulum, the notes we have been given show some hints to where we should be aiming to get. I have managed to get to \frac{d^2\theta}{dt^2} + \frac{g}{L}\theta = 0 However, the next line should be \theta = \theta_{max}...
  30. E

    Simple pendulum problem - confirmation

    Hi, I got this question: Ok, for the period: \frac{180\textit{s}}{72.0} = 2.50{\textit{s}} Then I found the pendulum equation that I don't understand well. I arraganged it to find the gravity: g = \left( \frac{2\pi\sqrt{\ell}}{T} \right) ^2 Then I plugged in the numbers and got the...
  31. J

    Simple Pendulum: Explaining Why Time is Proportional to Route Length

    hey people. i am new to these forums. i am doing some coursework on pendulums, for science. i have collected results, and have of course found t is proportional to route length. for my analysis, i need to say WHY, using some scientific knowledge. so why is it? also, why is t proportional...
  32. B

    Frequency of a simple pendulum and it's mass

    hi, i have a question "What are the relationships between the frequency of a simple pendulum and it's mass, amplitude abd length?" im pretty sure only the amplitude affects the pendulum while the mass and length don't right?
  33. C

    Exploring the Mechanics of a Suspended Baseball Bat: Simple Pendulum Explanation

    If you were to suspend a baseball bat from one end and let it swing back and forth, does it make a simple pendulum? Ok I think it doesn't because a baseball bat's upper portion(bat head) weighs more than the bottom so I figure that it will stop after one swing instead of swaying back and...
  34. U

    Calculating Time for a Simple Pendulum

    Consider the following problem: (this isn't homework, I thought this problem up myself and I'm wondering how to do it) ------------------------------------- You have a simple pendulum of mass M and a radius R, which is released from the horizontal. How much time does it take to reach the...
  35. B

    Simple Pendulum Angle Problem: Solving for Angular Acceleration

    You pull a simple pendulum of length 0.215 m to the side through an angle of 3.50 ^\circ and release it. i got 0.93, but it marked it wrong. i divided the mass over the accel of gravity, squared it and multiplied by 2pi. is this wrong?
  36. V

    Understanding the Dynamics of a Simple Pendulum

    A simple pendulum consists of a mas M suspended by a thin string. The magnitude of the tension is T. The mass swings back and forth between +,- theta0. I need help identifying which of the following statements are correct. These are my answers, but I'm getting something wrong. A)T=Mg at...
  37. C

    How Does Changing Mass, Length, or Gravity Affect a Pendulum's Period?

    A pendulum has a period of 1.8 s. a) Its mass is doubled. What is its period now? b) Its length is doubled. What is its period now? The original pendulum is taken to a planet where g = 16 m/s2. c) What is its period on that planet?
  38. J

    Help with Simple Pendulum Physics Homework

    Hey all, I'm a math students, and I've got physics homeworks to do, and... I need some help :smile: To make it short, I solved the approximation of the differential equation of the angle of a pendulum in function of time, and I got this...
  39. N

    Calculating Simple Pendulum Oscillation in a Moving Vehicle

    Simple pendulum has T = 2pi rt (l/g) when oscillating at a natural frequency of vibration. (Small angles of course) Calc. new T of pendulum when oscillating in a car with acceleration a. Any tips? Thanks. :)
  40. Reshma

    Simple pendulum, a conical pendulum and a compound pendulum?

    What is difference between a simple pendulum, a conical pendulum and a compound pendulum? In which category does a Foucault's pendulum fall in?
  41. K

    Calculating Period of a Simple Pendulum with Accelerating Elevator and Truck

    Okay I thought I understood this, but I guess not... according to this webassign program all my answers are wrong! >> A simple pendulum is 6.00m long. (a) What is the period of simple harmonic motion for this pendulum if it is hanging in an elevator that is accelerating upward at...
  42. B

    Questions about simple pendulum

    1) A simple pendulum consist of a mass m tied to a string (considered massless) of length L. So would a baseball bat suspended from one end, swinging back and forth, make a simple pendulum? No, right? because the "string" in this case is not massless. Does the string that is swinging the...
  43. E

    Simple Pendulum Problem: Solving for Amplitude without Small Angle Approximation

    could you pleassee help me get started on this problem...im not sure how do it 1. A simple pendulum problem of length l oscillates with an amplitude of 45degrees. (Do it without the approx. of sin(theta) = theta)(small angle approx.) any help would be awesome
  44. C

    3rd Harmonic Content for a Simple Pendulum?

    A simple pendulum of length l oscillates with an amplitude of 45°. What is the approximate amount of 3rd harmonic content in the oscillation of the pendulum? NOTE: the numerical answer is apparently 0.0032. I need to figure out how this was arrived at. \hline As a starting point...
  45. L

    Calculating g on an Unfamiliar Planet Using a Simple Pendulum

    After landing on an unfamiliar planet, a space explorer constructs a simple pendulum of length 47.0 cm. She finds that the pendulum makes 97.0 complete swings in a time of 141 s . What is the value of g on this planet? a complete swing is a cycle? so the period would be 97/ 141 = 0.688??is...
  46. E

    A Simple Pendulum and Friction problem

    Im supposed to calculate the work done by the frictional force on a simple pendulum after one period. I have to use the following equation to do this calculation. ((beta)^2)'= (2g/l)(cosbeta - costheta) where thetha is the the maximum angle of the motion. In other words theta is the angle...
  47. Rockdog

    What is the acceleration of a simple pendulum at the lowest point of its swing?

    A simple pendulum of mass 15 kg with a period of 1.8 sec is displaced an angle of 10 degrees from the vertical. What would its acceleration be in the vertical (y) direction as it reachs the lowest point on its swing? ********** Ok, I understand that it is a simple pendulum, but how do I...
  48. D

    Simple Pendulum Oscillation: Answers and Explanations for Common Test Questions

    Hello, I have two test questions that I missed AT school so i wrote them down. I wanted to know the correct answers as well as a short description of how they came up with that. 1) a simple pendulum consists of a mass attached to a weightless string L. For this system when undergoing small...
  49. W

    Simple pendulum and angular position

    Okay, I just took the final for my first DE class! I really liked it, now I can actually know how to derive some of these equations that they just hand to you in physics and chemistry. So anyway, there is the solution to the angular position(from vertical)of the simple pendulum; the one...
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