Two carts are rolling to the right along the same level track. cart 1, with a mass mi between 3.40 kg and 3.90 kg, is in the rear, rolling at a speed between 5.80 m/s and 6.50 m/s and catching up to cart 2, which is rolling at a speed between 2.80 m/s and 3.30 m/s. choose signs carefully; only speeds are given. a) cart 1 overtakes and collides with cart 2 and sticks to it (both have velcro pads). afterward, they both continue rolling right, now at a speed of 4.40 m/s what is cart 2's mass (m2)? b) a bit later, the joined carts suffer a head-on collision with a third cart (m between 6.00 kg and 7.00 kg), rolling left at a speed between 2.50 m/s and 3.50 m/s. this collision stops cart 2 completely, while knocking cart 1 left at 4.00 m/s. calculate the post-collision velocity of cart 3. c) is the predicted outcome of the second collision physically realistic in terms of energy? show all work and briefly explain.