1. The problem statement, all variables and given/known data A tractor has a belt pulley diameter of 10 inch operating at 1100 revolutions per minute. The pulley is connected by a belt to another machine that needs to operate at 650 rpm. What size should the pulley be on the second machine? 2. Relevant equations 2Pi*r 3. The attempt at a solution I don't really know where to start. I know that a wheels circumference is 2Pi*r The first wheel is 10 inches so 2*Pi*5 inches = 1100rpm if the second wheel has to operate at 650 can I get it by 650/2pi=103 inches?