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Momentum - Equation

Physics: AQA GCSE Higher, topic 5.3.10

Momentum

The momentum of an object is its mass multiplied by its velocity.

Equation for momentum

Equation for momentum

  • The equation for calculating momentum is:
  • p=mvp = mv
  • Momentum = mass × velocity
Units

Units

  • Momentum is measured in kg m/s.
  • Velocity is measured in m/s.
  • Mass is measured in kg.
Conservation of momentum

Conservation of momentum

  • The law of conservation of momentum says that momentum cannot be created or destroyed.
  • If two objects collide, the sum of momentum before the collision is equal to the sum of momentum after the collision.
Conservation of momentum equation

Conservation of momentum equation

  • The equation for the conservation of momentum is:
  • m1u1+m2u2=m1v1+m2v2m_1u_1 + m_2u_2 = m_1v_1 + m_2v_2
  • (Mass 1 × initial velocity 1) + (mass 2 × initial velocity 2) = (mass 1 × final velocity 1) + (mass 2 × final velocity 2)
  • In other words, the sum of the momentums of the two objects that are colliding will remain the same after they have collided.

Test yourself on Momentum - Equation

  • Usain has a mass of 90 kg and he is sprinting at a velocity of 10 m/s. What is his momentum?

  • Serena has a mass of 58 kg and she is sprinting at a velocity of 8 m/s. What is her momentum?

  • What is the equation for the conservation of momentum?

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