Basic Physics Concepts Lecture Notes

Introduction

• Overview of basic physics concepts:
  • Displacement
  • Velocity
  • Acceleration
  • Projectile Motion
  • Newton's Three Laws
  • Forces
  • Momentum

Distance and Displacement

• Distance is a scalar quantity:
  • Only magnitude
  • Example: Distance between two cities
• Displacement is a vector quantity:
  • Magnitude and direction
  • Example: Walking east 8 meters, then west 3 meters
  • Total distance: 11 meters
  • Net displacement: 5 meters
• Displacement equation: Final position - Initial position

Speed and Velocity

• Speed (scalar):
  • How fast something moves
  • Positive always
  • Example Formula: Speed = Distance / Time
• Velocity (vector):
  • Speed with direction
  • Can be positive or negative
  • Example Formula: Velocity = Displacement / Time

Acceleration

• Acceleration describes how fast velocity changes
  • Example: Sports car vs Truck
• Defined as: Change in velocity / Time taken
• Positive acceleration: Speed increases
• Negative acceleration: Speed decreases
• Formula: a = (v_final - v_initial) / t

Gravitational Acceleration

• Represents how velocity changes due to gravity
• Earth: g = -9.8 m/s²
• Affects vertical component of velocity

Projectile Motion

• Involves objects influenced by gravity
• 1D Projectile Motion: Motion in a single direction (e.g., dropping a ball)
• 2D Projectile Motion: Motion in both x and y directions (e.g., kicking a ball off a cliff)
• Horizontal velocity (vx) remains constant
• Vertical velocity (vy) changes due to gravity

Newton's Laws of Motion

1. First Law: Objects in motion stay in motion unless acted upon by a force
   • Inertia: Resistance to change in motion
   • Example: A hockey puck on ice
2. Second Law: F_net = m * a
   • Relationship between force, mass, and acceleration
   • Example: Calculating acceleration from force and mass

Conclusion

• Understanding these fundamental concepts provides a basis for further study in physics.
• Key takeaway: Differentiate between scalar and vector quantities.