1. The problem statement, all variables and given/known data A .2kg mass traveling on a frictionless horizontal surface at a speed of 3 m/s. It hits a 1.3 kg mass at rest that is connected to a massless spring with a a spring constant of 100 newtons per meter. The other end of the spring is fixed. Calculate the linear momentum and kinetic energy of the combined masses immediately after the impact. 2. Relevant equations I can calculate the combined momentum of the masses but I don't know what to do with the spring. 3. The attempt at a solution The inelastic equation formula is (m1)(v1) + (m2)(v2) = (m1 + m2)(vf) where vf is the new velocity and then I would just plug in vf into: KE = 1/2(m)(v)^2 as v and get the kinetic energy. My problem is I don't know what to do with the spring.