1. The problem statement, all variables and given/known data On a surface without friction, we have 3 blocs with mass A=0,4 kg B=0,1 Kg C=0,3 Kg which are placed one beside the other, with A being first, B second and C third.. If we push on the bloc A with a horizontal force of 2,4 N, determine what is the acceleration and what are the forces of the normals which are located between the blocs. http://imgur.com/F9PQwKK 2. Relevant equations Sum force of x = m * a(x) 3. The attempt at a solution I was able to resolve the problem and got the right answers. What I was wondering is why should I assume that the acceleration is going to be the same for the 3 blocs ? I was able to solve the problem because I assumed this to be true, but I don't know why it is. I guess that the fact there's no friction makes this true. any help ?