1. The problem statement, all variables and given/known data On a greasy, essentially frictionless lunch counter, a submarine sandwich of mass 0.480 kg, moving with speed 3.00 m/s to the left, collides with a grilled cheese sandwich of mass 0.270 kg moving with speed 1.10 m/s to the right. 1) If the two sandwiches stick together, what is the final velocity? (Take the positive velocities to the right.) 2) How much mechanical energy dissipates in the collision? 2. Relevant equations Pi = Pf ==> m1v1i + m2v2i = m1v1f + m2v2f KEi does not equal KEf KE = 0.5 m v^2 3. The attempt at a solution I figured out the first unknown, which came out to be -1.52 m/s. I have difficulty finding the answer to the second part "mechanical energy dissipates in the collision". i have no clue on how to approach to this in anyhow, I didn't stop working, i had calculated the initial kinetic energy of each particle before they collide which came out to be the following. KE for submarine sandwich = 2.16 J KE for the other sandwich = 0.16335 J and the Final Kinetic energy of the system should equal 0.8664 J can anyone please tell me how to figure out the answer for the second part of the question?