Q1. A typical Major League fastball is thrown at about 99 mph and with a spin rate of 103 rpm. If the distance between the pitcher's point of release and the catcher's glove is exactly 65.5 ft, how many full turns does the ball make between release and catch? Neglect any result of gravity or air resistance on the ball's flight.
Q2. Niobium metal becomes a superconductor when cooled below 9 K. Its superconductivity is destroyed when the surface magnetic field exceeds 0.100 T. In the absence of any external magnetic field, determine the maximum current a 1.53-mm-diameter niobium wire can carry and stay superconducting.