Kinetic energy in the center-of-mass frame

Two bodies of masses $4.0\mathrm{kg}$ and $1.0\mathrm{kg}$ move along the same line with velocities $2.0m/s$ and $-3.0m/s$. Compute the velocity of the center of mass, the kinetic energy in the center-of-mass frame and the maximum energy that a collision between the two bodies can dissipate.