On a greasy, essentially, frictionless lunch counter, a 0.290 kg submarine sandwich, moving 3.80 m/s to the left, collides with an 0.290 kg grilled cheese sandwich moving 1.50 m/s to the right.
a) How much mechanical energy is dissipated in the collision?
b) If the two sandwiches stick together, what is the final velocity, taking positive velocities to the right?