Two positively charged skaters, Stacy and Bob, are traveling straight towards each other on frictionless ice. Consider them to be point charges. When they are 5.0 m apart, Stacy feels an attractive electric force of 2.2 N towards Bob. (a) What is the magnitude of the attractive force that Bob feels from Stacy? (b) The magnitude of Stacy's charge is twice as much as Bob's. What is the magnitude of Bob's charge? (c) Bob has twice the mass that Stacy does. At the instant that they are 5.0 m apart, from Bob's reference frame, Stacy appears to be moving towards him with an acceleration of 7.3×10-2 m/s2. Find Stacy's mass.