Momentum

• What is momentum?

  Momentum is a property that all moving objects have.
• How is momentum calculated?

  Momentum is equal to the mass of an object multiplied by its velocity.
• What is the momentum of a 4500 kg dinosaur charging at 12 m/s?

  The momentum is $54,000 \text{ kg m/s}$.
• What is the momentum of a 1200 kg car traveling at 25 m/s?

  The momentum is $30,000 \text{ kg m/s}$.
• What type of quantity is momentum?

  Momentum is a vector quantity.
• What does it mean that momentum has both magnitude and direction?

  It means that momentum can be positive or negative depending on the direction of motion.
• What is the conservation of momentum principle?

  In a closed system, the total momentum before an event is the same as the total momentum after the event.
• How do you find the total momentum before a collision between two objects?

  • Add the momentums of both objects.
  • Example: Dinosaur momentum + Car momentum.
• What is the total momentum of a dinosaur with momentum $54,000 \text{ kg m/s}$ and a car with momentum $-30,000 \text{ kg m/s}$ before a collision?


  The total momentum is $24,000 \text{ kg m/s}$.
• What does a positive total momentum indicate about the direction of motion?

  A positive total momentum indicates motion to the right.
• How do you calculate the shared velocity of two colliding objects after they stick together?

  Velocity equals total momentum divided by combined mass.
• What is the combined mass of a 4500 kg dinosaur and a 1200 kg car?

  The combined mass is $5700 \text{ kg}$.
• What is the velocity of the combined dinosaur and car after the collision?

  The velocity is $4.4 \text{ m/s to the right}$.
• What happens to momentum when stationary objects are involved in an event?

  The total momentum before and after the event must be zero.
• What is the initial momentum of a gun before it is fired?

  The initial momentum is zero.
• How does the gun's momentum relate to the bullet's momentum after firing?

  The gun's momentum plus the bullet's momentum must equal zero.
• What is the momentum of a bullet with a mass of 5 grams fired at 120 m/s?

  The momentum is $0.6 \text{ kg m/s}$.
• How do you express the gun's momentum if its mass is 2 kg and its velocity is unknown?

  The gun's momentum can be expressed as $2v$.
• How do you find the recoil velocity of the gun after firing?

  Rearrange the equation to find $v$ from $2v +$$0.6 =$$0$.
• What is the recoil velocity of the gun if $v =$$-0.3 \text{ m/s}$?


  The recoil velocity is $-0.3 \text{ m/s}$.
• What is the symbol for momentum?

  The symbol for momentum is $p$.
• How can the momentum equation be expressed using its symbol?

  The momentum equation can be written as $p =$$mv$.
• What are the key concepts related to momentum discussed in the video?

  • Momentum is mass times velocity.
  • Momentum is a vector quantity.
  • Conservation of momentum principle.
  • Momentum can be zero for stationary objects.
  • Recoil momentum must equal bullet momentum.