A disc rotates about its axis of symmetry in a horizontal plane at a steady rate of 3.5 revolutions per second. A coin placed at a distance of 1.25cm from the axis of rotation remains at rest on the disc. Find the coefficient of friction between the coin and the disc. ( g=10m/s2 )
a. 0.5
b. 0.7
c. 0.3
d. 0.6