I need help, this is from the website webassign

2. [-/1 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A 0.207 kg plastic ball moves with a velocity of 0.30 m/s. It collides with a second plastic ball of mass 0.106 kg,which is moving along the same line at a speed of 0.10 m/s. After the collision, both balls continue moving in the same, original direction. The speed of the 0.106 kg ball is 0.26 m/s. What is the new velocity of the 0.207 kg ball? 4.0 m/s (in the original direction) 3. [-/1 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A 2581 kg van runs into the back of a 825 kg compact car at rest. They move off together at 8.5 m/s. Assuming the friction with the road is negligible, calculate the initial speed of the van. 4.0 m/s 4. [-/1 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Two freight cars, each with a mass of 3.1 x 105 kg, collide and stick together. One was initially moving at 2.2 m/s and the other was at rest. What is their final speed? m/s 5. [-/1 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A 0. 105-kg hockey puck moving at 21.0 m/s is caught and held by a 72.0 kg goalie at rest. With what speed does the goalie slide on the ice? 4.0 m/s 6. [-/1.5 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A 45.0 kg woman, riding on a 8.0 kg cart, is moving east at 5.0 m/s. The woman jumps off the front of the cart and lands on the ground at 7.0 m/s eastward. (a) Sketch the "before" and "after" situations and assign a + and - direction. (Sketch them in your journals - they may be included on a journal check!) (b) Find the cart's velocity after the woman jumps off. Magnitude 4.0 m/s Direction ---Select