This question may be a bit too basic for you all, but I'm trying to help my 8th grader with his homework. I have come across the following quandry. From his science book [Prentice Hall Science Explorer Physical Science (Virginia)] pg 326 "... all objects in free fall accelerate at the same rate regardless of mass." pg 322 (talking about moving a red wagon) "Another way to increase acceleration is to change the mass. According to the equation [Accel=Force/Mass], acceleration and mass change in opposite ways." How can these two statements both be true. Are they not mutually exclusive? If F=MA, then A=F/M, which means if you change the mass it HAS to affect acceleration. I don't understand. And PLEASE give the answer in small words. While familiar with the concepts and a straight A student decades ago, I've never had physics. (and I have to be able to explain this back to an eighth grader.) Thank you in advance.