Science Finals (Chapter 11)

• Law of Conservation of Momentum - states that the momentum of

  a system is constant if no external forces acting on the system
• Isolated - means that no external force is acting on the system.
• Collision - the interaction that occurs when two or more objects hit each other
• Elastic collision – collisions where both momentum and kinetic energy are conserved
• Perfectly inelastic collision – two bodies with equal masses join together during collision and move together as one body after collision
• Inelastic collision – objects with equal masses move off separately at different speeds in the same direction after collision
• Formula for Kinetic energy: KE = 0.5(mv)^2
• Perfectly inelastic collision – the total momentum is conserved, but the total kinetic energy before collision is not equal to the total kinetic energy after collision
• Elastic collision formula: KE before = KE after
• p1 / m1v1 = momentum of the first object before collision

  p2/ m2v2 = momentum of the second object before collision

  p1ʹ / m1v1' = momentum of the first object after collision

  p2ʹ / m2v2' = momentum of the second object after collision
• If it is a perfectly inelastic collision, the objects stick together.
• To find out whether it is elastic or inelastic collision, you have to compare their kinetic energy whether it's conserved or not.
• In an elastic collision, the total kinetic energy remains constant throughout the collision.