Name of Young Physicist_____________________________ Date _______ Block ____ IP 670 Conservation of Momentum – Homework 1. Car A crashes into Car B. Fill in the following tables to verify conservation of momentum. ELASTIC COLLISION (collide and bounce) Initial (before collision) Final (after collision) m1 v1 p1 = m1v1 m1 v1 p1 = m1v1 m2 v2 p2 = m2v2 m2 v2 p2 = m2v2 pT = p1 + p2 Car A Car B Total p Total p pT = p1 + p2 The total momentum before and after a collision is always the ________________. Standard(s): 2.5 TA: ________ Independence Level: __________% Assistance, coaching, prompting: _________________________________________________*P* 2. Train A (0.5 kg) is moving at 2 m/s and crashes into Train B (0.4 kg), which was at rest. The two stick together. Calculate their final velocity. BEFORE AFTER Train A Train B Train A v = 2 m/s v = 0 m/s v=? m = 0.5 kg m = 0.4 kg m = 0.5 kg + 0.4 kg Train B INELASTIC COLLISION (collide and stick) Initial (before collision) m1 Train A v1 Final (after collision) p1 = m1v1 Final v 0.5 kg 2 m/s m2 v2 p2 = m2v2 Train B m v= 0.5+0.4= 0.4 kg 0 m/s Total p p 0.9 kg pT = p1 + p2 Total p The two trains are traveling at ___________ m/s after the collision. Page 2 of 3 p m MCAS Questions 1. Two toy carts are about to collide, as shown in the diagram below. Cart 1 has a mass of 15 kg and is moving right at a speed of 2 m/s. Cart 2 has a mass of 5 kg and is moving left at a speed of 3 m/s. When they collide, the carts will stick together. Neglecting friction, what will be the velocity of the carts after the collision? (MCAS 2011 #29) A. 0.75 m/s left B. 0.75 m/s right C. 15 m/s left D. 15 m/s right 2. At an amusement park, bumper car X moves at a speed of 2.5 m/s toward car Y, which is at rest, as shown in the diagram below. Car X collides with car Y. How does the momentum of each car change after the collision? (MCAS 2010 #22) A. Car X’s momentum increases, and car Y’s momentum decreases. B. Car X’s momentum decreases, and car Y’s momentum increases. C. Car X’s momentum is unchanged, and car Y’s momentum increases. D. Car X’s momentum is unchanged, and car Y’s momentum decreases. Page 3 of 3

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