I was thinking about the impact of two bodies. Lets say that we don't know the Coeffient of Elaticity. We know the mass of the object being hit "m1", the the object hitting m1, "m2". given the velocity of m2, "v", what would the force on m1 be? First lets assume that m1 is some plane or another, that cannot be moved. (Elasticity=0 "ε") since ε=0, the object will not bounce off of the surface. Therefore we can assume that the final velocity of m2 will be 0. therefore the (de)acceleration is equal to the incident velocity of m2. newtons 3rd law states thats the the negative force that deaccelerates m2 is equal to the force m2 is applying to m1. Therefore m2 is applying [m2*v] units of force, is it? would the mass for the force (F=ma) on m1 be the mass of the object hitting m1 or the object itself, m2? also, for kilograms and meters per second, do you get Newtons in force? Thanks.