4. In an isolated system, a 2kg ball with an initial velocity of 3 mfs hits a 5 kg ball that is initially at rest. What is the total kinetic energy before the collision? If the total kinetic energy after the collision is the same as that before the collision, is this an elastic collision or inelastic collision\"? Hint: See Sample Question 4 in the Unit IV Lesson and Example 7 on page 185 in the textbook