A penny is placed on an LP record that is slowly accelerating up to 78 revolutions per minute. It is found that if the penny is placed at 0.080 m or greater from the centre, then the penny slides off the edge of the record. Find the coefficient of static friction if the mass of the penny is 0.0032 kg. The turntable of a record player rotates at 33.33 rev/min and takes 20.0 s to reach this speed from rest. Calculate: a. Its angular acceleration. b. The number of revolutions it makes before reaching its final speed.