What is Turntable: Definition and 103 Discussions

A phonograph, in its later forms also called a gramophone (as a trademark since 1887, as a generic name in the UK since 1910) or since the 1940s called a record player, is a device for the mechanical recording and reproduction of sound. The sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc, called a "record". To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, very faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm which produced sound waves which were coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones.
The phonograph was invented in 1877 by Thomas Edison. Alexander Graham Bell's Volta Laboratory made several improvements in the 1880s and introduced the graphophone, including the use of wax-coated cardboard cylinders and a cutting stylus that moved from side to side in a zigzag groove around the record. In the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center, coining the term gramophone for disc record players, which is predominantly used in many languages. Later improvements through the years included modifications to the turntable and its drive system, the stylus or needle, and the sound and equalization systems.
The disc phonograph record was the dominant audio recording format throughout most of the 20th century. In the 1980s, phonograph use on a standard record player declined sharply due to the rise of the cassette tape, compact disc, and other digital recording formats. However, records are still a favorite format for some audiophiles, DJs, collectors, and turntablists (particularly in hip hop and electronic dance music), and have undergone a revival since the 2000s.

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  1. B

    Concept Question. Record turntable rotates at constant angular velocity.

    Homework Statement Suppose a record turntable rotates at constant angular velocity. a) Does a point on the rim have radial and/or tangential acceleration? b) If the turntable's angular velocity increases uniformly, does the point have radial and/or tangential acceleration? c) For which...
  2. C

    Angular Momentum of a turntable with frictionless bearings

    Homework Statement You are standing on the edge of a turntable with frictionless bearings. It is initially rotating when you catch a ball, which is moving in the same direction but faster than you are moving and on a line tangent to the edge of the turntable. Assume you do not move relative...
  3. D

    Inexpensive motorized turntable up to 10 lb load

    Hello, I'm trying to design and fabricate a dc motorized turntable (24" diameter fairly light-weight pressed wood table top) to rotate at various slow speeds between 1 revolution per hour to perhaps as fast as one revolution per minute carrying a load of up to 10 pounds on a lazy susan type...
  4. A

    Momentum Conservation of Turntable and Beetle System

    Homework Statement A beetle with a mass of 30.0 g is initially at rest on the outer edge of a horizontal turntable that is also initially at rest. The turntable, which is free to rotate with no friction about an axis through its center, has a mass of 80.0 g and can be treated as a uniform...
  5. A

    Calculating Torque for a LP Turntable

    Homework Statement An LP turntable must spin at 3.52 rad/s to play a record. How much torque must the motor deliver if the turntable is to reach its final angular speed in 1.7 revolutions, starting from rest? The turntable is a uniform disk of diameter 30.8 cm and mass 0.26 kg. Homework...
  6. D

    Angular Velocity of a turntable after weights are added

    A 2.0 {\rm kg}, 20-cm-diameter turntable rotates at 100 {\rm rpm} on frictionless bearings. Two 500 {\rm g} blocks fall from above, hit the turntable simultaneously at opposite ends of a diagonal, and stick. What is the turntable's angular velocity, in rpm, just after this event? I'm not...
  7. C

    Angular velocity for a turntable

    Homework Statement A turntable that is initially at rest is set in motion with constant angular acceleration a. What is the angular velocity of the turntable after it has made one complete revolution? Homework Equations 2(pi)rads=1 revolution the 3 constant acceleration equations, i...
  8. W

    Coefficient of Static Friction Mass on Turntable

    Homework Statement A block of mass 3.5kg rests on a rough horizontal turntable at a distance of 1.2m from the axis of rotation. If the block begins to slide when the turntable is rotating at 20.0 rev/min, what is the coefficient of static friction between the block and the turntable...
  9. W

    What is the Best Turntable for Outdoor Monitoring?

    I need an external turntable that I can control automatically by a routine which I will write in either Visual Basic 6, C or Visual C++. So I need a suitable interface to do this It will sit on my balcony overlooking the sea and will have a couple of dome cameras mounted on it which will...
  10. T

    Calculating the Angular Velocity of a Turntable After Blocks Are Dropped on It

    Homework Statement A 2.05 kg, 33.64 cm diameter turntable rotates at 365 rpm on frictionless bearings. Two 280 g blocks fall from above, hit the turntable simultaneously at opposite ends of a diagonal, and stick. What is the turntable's angular velocity, in rpm, just after this event...
  11. J

    Coin on Turntable: Find Max Distance w/o Slipping

    Homework Statement A coin is placed on a turntable that is rotating at 45.0 rpm. If the coefficient of static friction between the coin and the turntable is 0.186, how far from the center of the turntable can the coin be placed without having it slip off? Homework Equations mv^2/r <=...
  12. Y

    Blocks on turntable with friction = hard problem

    Two identical blocks are tied together with a string and placed along the same radius of a turntable that is spinning about its center. The inner block is 4 cm from the center and the outer block is 5 cm from the center. The coefficient of static friction between the turntable and the blocks is...
  13. T

    Finding the Maximum Angular Frequency for Blocks on a Turntable

    Homework Statement Two identical blocks are tied together with a string and placed along the same radius of a turntable that is spinning about its center. The inner block is 4 cm from the center and the outer block is 5 cm from the center. The coefficient of static friction between the...
  14. A

    Turntable Rotation with weight on edge v. in the center

    Homework Statement A man (mass m1 = 100 kg) stands at the fringe of the large rotary table (radius R = 5 m, massm2 = 100 x m1), which rotates at a frequency of 10/min. The man goes along a radius line towards the table center until he reaches the rotation axis. The spatial extent of the man...
  15. S

    DDWFTTW Turntable Test: 5 Min Video - Is It Conclusive?

    I have built a turntable and “cart” to test the claim of being able to travel directly downwind faster than the wind using only the immediate force of the wind. Here is a video of the test. The turntable is level but looks like it’s on an angle because of the camera angle. The cart ran against...
  16. R

    What is the tension in the string for two blocks on a spinning turntable?

    Two identical blocks are tied together with a string and placed along the same radius of a turntable that is spinning about its center. The inner block is 4 cm from the center and the outer block is 5 cm from the center. The coefficient of static friction between the turntable and the blocks is...
  17. L

    Finding Maximum Angular Frequency and Tension on a Turntable

    Homework Statement Two identical blocks are tied together with a string and placed along the same radius of a turntable that is spinning about its center. The inner block is 3 cm from the center and the outer block is 5 cm from the center. The coefficient of static friction between the...
  18. H

    Turntable Acceleration question

    Homework Statement A point on a rotating turntable 20.0 cm from the center accelerates from rest to a final speed of .700m/s in 1.75s. At t=1.25s, find the magnitude and direction of (a) the radial acceleration, (b) the tangential acceleration, and (c) the total acceleration at that point...
  19. W

    The effect of a spinning wheel on a turntable

    Homework Statement A person stands at rest on a 5.0kg, 50cm diameter frictionless turntable. He receives spinning bicycle wheel, 180rpm counterclock wise, diameter 64cm, and the rim weighs 4.0kg. The wheel was held in a horzontal plane, the handles extend outward from the center...
  20. S

    "Understand Motion of Block on Turntable

    Turntable ?? Homework Statement A block of mass M is place a Distance R from the center of a turntable rotating at W radians/sec. A. If the turntable is a frictionless surface, explain the motion of the block. B. If the turntable has coefficient of static Friction Us and the block is ready...
  21. M

    Angular momentum of merry go round turntable

    Hi, I got this question wrong on a test and am really quite lost about it. I'd appreciate somebody running me through it. --- "Suppose a 55 kg person stands at the edge of a 6.5 m diameter merry go round turntable that is mounted on a frictionless bearing and has a moment of inertia of...
  22. B

    Linear Acceleration of a turntable

    Problem: What is the linear acceleration of a point on the rim of a 36 cm diameter turntable which is turning at 33 rev/min? My Work: T = \frac{2 \pi r}{v}; v = \frac{2 \pi r}{T} a_{r} = \frac{v^{2}}{r} \frac{33 rev}{min} \times \frac{1 min}{60 sec} = \frac{.55 rev}{sec} \frac{2...
  23. clope023

    Speed and accleration of a turntable

    Homework Statement An electric turntable 0.740m in diameter is rotating about a fixed axis with an initial angular velocity of 0.290rad/s . The angular acceleration is 0.900rad/s^2 . a) Compute the angular velocity after a time of 0.194s. - .465rev/s b) Through how many revolutions...
  24. X

    Conservation of Angular Momentum of Turntable

    [SOLVED] Conservation of Angular Momentum Homework Statement A 60-kg woman stands at the rim of a horizontal turntable having a moment of inertia of 500 kgm^{}2 and a radius of 2.00 m. The turntable is initially at rest and is free to rotate about a frictionless, vertical axle through its...
  25. W

    (101)Horizontal/Vertical forces on an object by a turntable

    [SOLVED] (101)Horizontal/Vertical forces on an object by a turntable I am taking PHY 101, which I am having a little trouble with. I took a physics course in high school which I really enjoyed; a lot of what I am doing is familiar, but the specifics confuse me occasionally. I know I have solved...
  26. G

    Record & Turntable: Final Rotational Kinetic Energy

    Homework Statement Consider a turntable to be a circular disk of moment of inertia I_t rotating at a constant angular velocity w_i around an axis through the center and perpendicular to the plane of the disk (the disk's "primary axis of symmetry"). The axis of the disk is vertical and the...
  27. U

    Frictional coin sliding on turntable

    A 5.0 g coin is placed 22 cm from the center of a turntable. The coin has static and kinetic coefficients of friction with the turntable surface of µs = 0.80 and µk = 0.50. What is the maximum rpm that the turntable could speed up to without the coin sliding off? m = .005 kg r = .22 m...
  28. U

    Frictional coin sliding on turntable

    A 5.0 g coin is placed 22 cm from the center of a turntable. The coin has static and kinetic coefficients of friction with the turntable surface of µs = 0.80 and µk = 0.50. What is the maximum rpm that the turntable could speed up to without the coin sliding off? m = .005 kg r = .22 m µs = 0.8...
  29. J

    Equations of motions, revolutions of turntable

    Homework Statement A turntable reaches an angular speed of 45.0 rpm, in 2.1 s, starting from rest. (a) Assuming the angular acceleration is constant, what is its magnitude? _2.24_rad/s2 (b) How many revolutions does the turntable make during this time interval? ______ rev...
  30. V

    A Mass on a Turntable: Conceptual

    Homework Statement A small metal cylinder rests on a circular turntable that is rotating at a constant rate. Let R be the distance between the cylinder and the center of the turntable. Now assume that the cylinder is moved to a new location R/2 from the center of the turntable. Which of the...
  31. M

    No solution can be attempted without the mass of the block.

    Homework Statement The coefficient of friction between a certain brass block and a large revolving turntable is µ = 0.18. How far from the axis of rotation can the block be placed before it slides off the turntable if it is rotating at 33 1/3 rev/min? Homework Equations how can i do...
  32. B

    Turntable rotation rate Problem

    Homework Statement Shown from the top view are six blocks that are sitting at rest on rotating turntables. All of the turntables have the same rotation rate (i.e. same frequency). The masses of the blocks and how far out from the center they sit varies. The specific values are given in the...
  33. O

    Radial acceleration of a turntable

    This is from an example in a book: On a horizontal turntable that is rotating at constant angular speed, a bug is crawling outward on a radial line such that its distance from the center increases quadratically r=bt^2, \theta=\omegat where b, \omega are constants. The example then solves for...
  34. russ_watters

    What are Opinions on USB Turntables for Digitizing LPs?

    I have some lp's I'd like to digitize. Anyone have any opinions on USB turntables such as these?: http://www.buy.com/retail/searchresults.asp?querytype=home&qu=usb+turntable&qxt=home&display=col&dclksa=1
  35. V

    Particle sliding off turntable - find friction

    Homework Statement A turntable rotates at 78 rev/min A particle on the turntable is located 0.14 m from the center of the rotating turntable The particle on the turntable has a mass of 16 g. Calculate the force of friction which keeps it from sliding off Homework Equations f_s =...
  36. A

    Turntable, block, and rotation angular velocity

    Homework Statement A 200g, 40-cm-diameter turntable rotates on frictionless bearings at 60 rpm. A 20g block sits at the center of the turntable. A compressed spring shoots the block radially outward along a frictionless groove in the surface of the turntable. What is the turntable's rotation...
  37. P

    Cat & Turntable: Angular Velocity Comparison?

    If there's a cat and a turntable both of same mass each... and the cat starts walking around the edge of the turntable which is initially at rest, how would the angular velocity of the two objects compare? Would the cat move at all since it has the same mass as the turntable and momentum has to...
  38. M

    Calculate Torque Needed to Spin an LP Turntable 648 Degrees

    An LP turntable must spin at 3.51 rad/s to play a record. How much torque must the motor deliver if the turntable is to reach its final angular speed in 1.8 revolutions, starting from rest? The turntable is a uniform disk of diameter 31 cm and mass 0.26 kg. I know that 1.8rev is equal to 648...
  39. V

    Angular Momentum Problem of turntable

    This seems pretty basic but I am drawing a blank. Thanks in advance. "A cat is sitting on the rim of a wooden turntable that is free to turn about a vertical axis. The turntable's mass is 3 times the cat's mass and is initially at rest. The cat then starts walking around the rim at a speed of...
  40. K

    Max Speed of 0.20 kg Mass on Rotating Turntable

    Information given: A small metal cylinder rests on a circular turntable that is rotating at a constant speed as illustrated in the diagram View Figure . The small metal cylinder has a mass of 0.20 \rm kg, the coefficient of static friction between the cylinder and the turntable is 0.080...
  41. W

    Angular momentum and a turntable

    Angular momentum... A uniform disk has a mass of 3.7 kg and a radius of 3.8 m. The disk is mounted on frictionless bearings and is used as a turntable. The turntable is initially rotating at 20 rpm. A thing walled hollow cylinder has the same mass and radius as the disk. It is released from...
  42. D

    How do the casters on a turntable support the weight of a motorcycle?

    Hi: New to this forum and have a quick question. Hope I'm posting in the right area. First of all, I'm not an engineer, nor do I pretend to be one but I'm having to settle an argument between two people who think they are. There is a ten foot diameter turntable constructed of a 2" steel...
  43. kreil

    Angular Momentum of a turntable

    I have tried this problem many times, but I can't even get it started really. Any hints are appreciated! A 60.0 kg woman stands at the rim of a horizontal turntable having a moment of inertia of 500kg/m^2 and a radius of 2 meters. The turntable is initially at rest and is free to rotate about...
  44. H

    Max Distance Block Can Be Placed Before Sliding Off Turntable

    The coefficient of friction between a certain brass block and a large revolving turntable is µ = 0.09. How far from the axis of rotation can the block be placed before it slides off the turntable if the turntable rotates at a constant rate of 33 1/3 rev/min (so that it requires time T = 60/33.33...
  45. H

    Maximum Angular Frequency for Blocks Tied on Spinning Turntable

    Two identical blocks are tied together with a string and placed along the same radius of a turntable that is spinning about its center. The inner block is 4 cm from the center and the outer block is 5 cm from the center. The coefficient of static friction between the turntable and the blocks is...
  46. B

    Suppose a small coin is on a flat horizontal rotating turntable

    and does not slide off. in this case does centripetal force = frictional force? I think the answer is yes, but want to make sure. thanks
  47. A

    Conservation of angular momentum of a turntable

    Please help. Consider a turntable to be a circular disk of moment of inertia I_t rotating at a constant angular velocity omega_i around an axis through the center and perpendicular to the plane of the disk (the disk's "primary axis of symmetry"). The axis of the disk is vertical and the disk...
  48. M

    Solve Turntable Problem: Find Coefficient of Friction

    A coin is placed 10.0 cm from the axis of a rotating turntable of variable speed. When the speed of the turntable is slowly increased, the coin remains fixed on the turntable until a rate of 36 rpm is reached, at which point the coin slides off. What is the coefficient of static friction between...
  49. T

    Max Speed for 0.20kg Mass on Rotating Turntable

    [FONT=Times New Roman]I need help with this one problem: A small metal cylinder rests on near the edge of a circular turntable that is rotating at a constant speed. The small metal cylinder has a mass of 0.20 kg, the coefficient of static friction between the cylinder and the turntable is...
  50. S

    How Far Can the Block Be Placed on a Rotating Turntable Without Sliding Off?

    The coefficient of friction between a certain brass block and a large revolving turntable is µ = 0.26. How far from the axis of rotation can the block be placed before it slides off the turntable if it is rotating at 33 1/3 rev/min? :confused: :frown: :smile:
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