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.
The axle of a wheel is mounted on supports that rest on a rotating turntable as shown in Fig. 10-50. The wheel has angular velocity w1 = 50.0 rad/s about its axle, and the turntable has angular velocity of w=35.0 rad/s about a vertical axis. (Note arrows showing these motions in the figure.)...
Hi all,
I haven't studied rotational physics in a long time so this may be a stupid question, but here goes. I'm trying to model the properties of a turntable (record player). Using the theories of rotational motion, is it possible to calculate the time it would take for the spinning...
Please help
When a turntable rotating at 32 1/3 rev/min is shut off, it comes to rest in 29 s.
a assuming constant angular accelerationn, find the angular acceleration.
(my work) W-Wo/t=a and I got -.12
b number of revolutions
(my work) phida-initial phida= Wot + 1/2at^2 and I got...