Many phonographs records were thin plastic discs with a diameter of 7, 10, or 12 inches (18, 25, or 30 cm). A 7 inch single is normally played at 45 revolutions per minute (rpm). A 12 inch long-playing record (LP) is normally played at 33 1/3 rpm. Old-fashioned 10 inch records were played at 78 rpm. There has been much change for the speeds of the phonograph. Due to the evolution of the way people think. An LP is able to hold about 30 minutes of sound per side.
In this essay, we are concerned with the linear speed; that is, v.
v = s /t or 2*pi*r/T
Where s is displacement, t is time, r is radius, and T is period. Since we have the diameters of the records in inches we need to convert them to the radius in meters. The period is 60 seconds divided by the number of rpm's.
A 78 rpm record with a 10 in diameter
V = 2*pi*(05 in)(.0254 m/in)(78 rpm)/(60 s/min) = 1.04 m/s
WELL ya did ask...