Lecture Notes: Impulse and Momentum

Key Concepts

• Conservation of Matter and Energy
  • Chemistry: Conservation of matter
  • Physics: Conservation of energy
  • Extended to: Conservation of Momentum

Definitions and Units

• Momentum (P)
  • Definition: Mass times velocity
  • Nature: Vector quantity
  • SI Units: Kilogram meters per second (kg·m/s)

Understanding Momentum

• Momentum increases with:
  • Increased velocity (e.g., ball rolling downhill)
  • Increased mass (e.g., boulder vs. hailstone)

Practical Examples

• Cars in Motion
  • Momentum = Mass × Velocity
  • Stopping involves applying force over time
    • Small force + long time (e.g., letting friction stop the car)
    • Large force + short time (e.g., braking)

Impulse

• Definition

  • Impulse = Force (F) × Time (ΔT)
  • Measured in Newton seconds (N·s)

• Impulse-Momentum Theorem

  • Impulse = Change in Momentum (ΔP)
  • Formula: F ΔT = mv_final - mv_initial

Conservation of Momentum

• Principle

  • Total momentum remains constant before and after a collision

• Examples

  • Falling: Impact force is less on a trampoline due to time duration
  • Baseball: Swinging through maximizes force by increasing contact time
  • Pool Table: Collision transfers momentum from one ball to another

Implications of the Theorem

• Large force in instantaneous impacts
• Smaller force with extended duration impacts

Conclusion

• Upcoming Topics: Further discussion on collisions
• Comprehension Check: Encouraged viewers to test their understanding

Additional Notes

• Encouragement to subscribe and support additional content creation by Professor Dave.