Astudent solving for the acceleration of an object has applied appropriate physics principles and obtained the expression a=a1+fm where a1=3.00 meter/second2, f=12.0 kilogram⋅meter/second2 and m=7.00 kilogram. which of the following is the correct step for obtaining a common denominator for the two fractions in the expression in solving for a? 1. (m/m times a1/1) + (1/1 times f/m) 2. (1/m times a1/1) + (1/m times f/m) 3. (m/m times a1/1) + (f/f times f/m) 4. (m/m times a1/1) +(m/m times f/m )