5.7.2 Conservation of Momentum

• What does the Conservation of Momentum principle state?

  The total momentum of a closed system remains constant if no external forces act on it.
• Why is the Conservation of Momentum important in physics?

  It is crucial for analyzing collisions and explosions.
• How is momentum defined in physics?

  Momentum is defined as the product of an object's mass and its velocity.
• What is the formula for calculating momentum?


  p = m · v
• What units are used to measure momentum?

  Momentum is measured in kg·m/s.
• What does a closed system mean in the context of momentum?

  A closed system is one where no external forces influence the total momentum.
• What happens to momentum in elastic collisions?

  Both momentum and kinetic energy are conserved in elastic collisions.
• What occurs in inelastic collisions regarding momentum and kinetic energy?

  Momentum is conserved, but kinetic energy is not conserved in inelastic collisions.
• How is momentum treated in explosions?

  Momentum is conserved in explosions.
• If two ice skaters push off each other, how can you check if momentum is conserved?

  By calculating the total momentum before and after the push and comparing them.
• What is the process to check momentum conservation in the example of two ice skaters?

  1. Calculate total momentum before the push (initially at rest).

  2. Calculate momentum of each skater after the push.

  3. Add the momenta of both skaters after the push.

  4. Compare total momentum before and after the push.
• In the example of the ice skaters, what was the mass of Skater A?

  50 kg
• What was the velocity of Skater A after they pushed off each other?

  3 m/s
• What was the velocity of Skater B after they pushed off each other?

  • 2.14 m/s
• What does the total momentum after the push indicate in the ice skater example?

  It indicates an error in measurement or calculation since it should be zero.
• What was the mass of the stationary rocket in the explosion example?

  1000 kg
• What was the mass of Fragment A after the rocket explosion?

  400 kg
• What was the velocity of Fragment A after the explosion?

  10 m/s
• How do you calculate the velocity of Fragment B in the explosion example?

  By setting the total momentum after the explosion to zero and solving for \( v_B \).
• What was the calculated velocity of Fragment B?

  • 6.67 m/s
• In what way is momentum conservation applied in traffic accidents?

  It helps in reconstructing accidents and understanding the forces involved.
• How is momentum conservation relevant in sports?

  It helps in analyzing collisions between players or objects to optimize performance and safety.
• Why is momentum conservation important in space missions?

  It is used to calculate trajectories and maneuver spacecraft.
• What are the key points summarized about momentum and its conservation?

  • Momentum is the product of mass and velocity.
  • In a closed system, total momentum before an event equals total momentum after the event.
  • Momentum is conserved in elastic and inelastic collisions and explosions.
  • Understanding conservation of momentum is crucial for analyzing physical interactions and ensuring accurate calculations.