Physics problem help ---- finding speed & kinetic energy from weight and velocity?

Question

A model-train car of mass 260 g traveling with a speed of 0.50 m/s links up with another car of mass 430 g that is initially at rest.

(a) What is the speed of the cars immediately after they have linked together?

_____m/s

(b) Find the initial kinetic energy.

_____mJ

(c) Find the final kinetic energy.

_____mJ

Answer 1

a.

0.188 m/s

b.

0.0325 J

c.

0.012 J