Conservation of Momentum

• Law of Conservation of Momentum

  • momentum of any closed and isolated system will remain the same

  • P_{Total-Initial} = P_Total-Final

  • P_{A Initial} + P_{B Initial} = P_{A Final} + P_{B Final}

• Closed Isolated System

  • No added or removed bodies

  • No outside forces

  • Internal forces do not create change in a system

    • External forces do

• Types of Collisions (Interactions)

  • 1. Explosion

    • 0 = m_A V_{A Final} + m_B V_{B Final}

    • 0 = P_{A Final} + P_{B Final}

  • 2. Elastic

    • Collide and separate (snap back)

    • Magnet collisions = perfect elastic

    • m_A V_{A Initial} + m_B V_{B Initial} = m_A V_{A Final} + m_B V_{B Final}

  • 3. Inelastic

    • Collide and don’t separate

    • m_A V_{A Initial} + m_B V_{B Initial} = (m_A + m_B) V_Final