Q1. A coin is placed 12.0 {rm cm} from the axis of a rotating turntable of variable speed. When the speed of the turntable is slowly increased, the coin remains fixed on the turntable until a rate of 30.0 {rm rpm} (revolutions per minute) is reached, at which point the coin slides off. What is the coefficient of static friction between the coin and the turntable?
Q2. The power rating of the resistor is the maximum power it can safely dissipate without getting too hot. Presume you have a set of 5.37 Omega, 10.5 Omega, and 20.6 Omega resistors, all rated at 2.42 W. If you connect these 3 resistors in series across a variable emf source of negligible internal resistance, what is the largest potential difference this emf source can be set to without damaging any of resistors?