1. The problem statement, all variables and given/known data This is just a question relating to an assignment im doing, if a steel block mass m1 travelling at velocity v1 and friction of 0.1 hits a concrete barrier travelling at 0 with mass m2 with friction 0.6. they have an inelastic collision and travel 0.1m together. 2. Relevant equations frictional force = mg*coefficient of friction g=gravity=9.81m/s 3. The attempt at a solution for this period of travel, is the friction force acting on the both items = m1*g*0.1+m2*g*0.6 or is it (m1+m2)g*0.6?