1. The problem statement, all variables and given/known data Cart 1 has a mass of 1.5 kg and is moving on a track at 36.5 cm/s [E] toward cart 2. The mass of cart 2 is 5 kg, and it is moving toward cart 1 at 42.8 cm/s [W]. The carts collide. The collision is cushioned by a Hooke's law spring, making it an elastic head-on collision. Calculate the final velocity of each cart after collision. 2. Relevant equations 3. The attempt at a solution I plugged all my values into the head-on elastic collision formulas and I got vi1=84cm/s but the answer in the book is 3.15cm/s. I am really sure I have the right answer. Is there a mistake in the book?