1. The problem statement, all variables and given/known data The centripetal force acting on an object is doubled. The radius is also doubled. The speed of the object: (a) increases by a factor of 4 (b) increases by a factor of 2 (c) decreases by a factor of 2 (d) The change in the object's speed depends on its mass 2. Relevant equations F = mv2/r 3. The attempt at a solution So if I substitute 2's in for F and r in the above equation, my 2's cancel but the correct answer is a. ???