Lecture Notes: Speed and Velocity

Introduction to Speed

• Definition: Speed is the amount of distance covered in a given amount of time.
  • Formula: Speed = Distance / Time
  • Indicates how fast an object moves.
• Example: Traveling at 50 meters per second for one minute covers 3000 meters.
• Characteristic: Speed is a scalar quantity.
  • Has only magnitude, no direction.

Distance vs. Displacement

• Distance: Total ground covered, regardless of direction.
• Displacement: Distance covered in a specific direction.
  • Example: Traveling a 50 km route from A to B, where the actual distance between A and B is 20 km, results in a displacement of 20 km north.

Understanding Velocity

• Definition: Velocity is speed with a specified direction of motion.
  • Defines both magnitude and direction.
• Example: Traveling north at 50 meters per second for one minute.
• Characteristic: Velocity is a vector quantity.
  • Must include the direction.
• Units: Measured in meters per second (SI units).
  • Uniform measurement system (SI - International system of units).

Speed vs. Velocity

• Speed: Scalar quantity, magnitude only.
• Velocity: Vector quantity, includes magnitude and direction.

Average Speed and Average Velocity

• Average Speed
  • Formula: Total Distance / Total Time
  • Example: 50 km route in 2 hours = 25 km/h.
• Average Velocity
  • Formula: Displacement / Time
  • Example: Displacement of 20 km north in 2 hours = 10 km/h.

Concept of Average Velocity

• Example Question: Formula 1 race (300 km race in 1 hour 40 minutes, starting and ending at the same point)
  • Displacement = 0, thus average velocity = 0 m/s.

Summary

• Speed and velocity are fundamental concepts in physics.
• Speed is a scalar, velocity is a vector.
• Importance of direction in defining velocity.
• Understanding average speed and average velocity helps in analyzing motion effectively.
  • Displacement plays a key role in determining average velocity.