A coin is kept a distance of 10 cm from the centre of a circular turn table. If the coefficient of static friction between the table and the coin is 0.8. Find the frequency or rotation of the disc at which the coin will just begin to slip

Explanation

Distance of coin = r = 10 cm = 0.1 m.
Coefficient of friction `mu` = 0.8.
Frequency of rotation = number of rotations per second.
For coin not to slip `mumg = mromega^2 rArr omega = sqrt((mug)/(r))`
`therefore omega sqrt((0.8xx9.8)/(1)) = sqrt(78.4)` 8.854 rad/ sec.
Number of rotations per sec = Rotational
frequency ` = (omega)/(2pi) = (8.854)/(2pi)` =1.409 Rot/sec or 84.54 r.p.m..