Physics Basics Lecture Notes

Introduction

• Topics Covered: Displacement, velocity, acceleration, projectile motion, Newton's laws, forces, momentum.
• Purpose: Basic introduction to physics principles.

Distance and Displacement

• Distance: How far something has traveled, a scalar quantity (e.g., 100 miles).
• Displacement: Distance with direction, a vector quantity.
  • Example: Walk 8 meters east, 3 meters west; Distance = 11 meters, Displacement = 5 meters east.
• Key Points:
  • Distance is always positive.
  • Displacement can be positive or negative based on direction.
  • Scalars have magnitude only; vectors have magnitude and direction.

Speed and Velocity

• Speed: How fast something is moving, a scalar (e.g., 30 meters per second).
• Velocity: Speed with direction, a vector.
  • Example: Train moving at 30 meters/second west is velocity.
• Formulas:
  • Speed = Distance / Time
  • Velocity = Displacement / Time
• Key Points:
  • Speed is always positive.
  • Velocity can be positive or negative.
  • Average speed = Total distance / Total time.
  • Average velocity = Displacement / Total time.

Acceleration

• Definition: How fast the velocity is changing.
  • Positive acceleration: Speeding up.
  • Negative acceleration: Slowing down.
• Formula:
  • Acceleration = (Final Velocity - Initial Velocity) / Time
• Examples:
  • Truck vs. Sports car acceleration.

Gravitational Acceleration

• Earth's Gravitational Acceleration (g): -9.8 m/s²
  • Impacts vertical (y-direction) motion.
  • Causes velocity to decrease as it moves upward.

Projectile Motion

• Definition: Objects moving under the influence of gravity.
• Components:
  • Horizontal motion (x-axis): Constant velocity.
  • Vertical motion (y-axis): Affected by gravity.
• Key Points:
  • No horizontal acceleration; horizontal velocity (Vx) is constant.
  • Vertical velocity (Vy) changes due to gravity.

Newton's Laws of Motion

Newton's First Law

• Concept: An object at rest stays at rest; an object in motion stays in motion unless acted upon by a force.
• Example: Friction stopping a moving object.

Newton's Second Law

• Formula: Net Force = Mass x Acceleration (F = ma)
• Example:
  • Applying a force to a mass accelerates the object.
  • Calculation of acceleration using given force and mass.

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This summary captures the main points from the lecture on basic physics concepts, including definitions, examples, and key formulas. It should be useful for reviewing the foundational principles of physics.