1. The problem statement, all variables and given/known data A certain force gives object m1 an acceleration of 12.0 m/s2. The same force gives object m2 an acceleration of 3.30 m/s2. What acceleration would the force give to an object whose mass is (a) the difference between m1 and m2 and (b) the sum of m1 and m2. 2. Relevant equations F=ma 3. The attempt at a solution I found these two solutions online: http://www.physforum.com/index.php?showtopic=6754 http://www.jiskha.com/display.cgi?id=1286634662 but I can't follow their math. I tried manipulating the above equation similarly, to no avail. Any help is greatly appreciated!