GEN P6

Lesson Overview

  • Lesson Title: Horizontal General Motion

  • Prepared by: Ms. Carissa G. Balagbag

Understanding Physics

  • Definition of Physics: A branch of science that deals with the interaction of matter, force, and energy.

    • Physics is essential for engineering and technology development.

    • Quote: "No engineer could design... without first understanding the basic laws of physics." - Young & Freedman (2012)

The Importance of Physics

  • Curiosity: Addresses everyday phenomena such as the blue sky, the behavior of radio waves, and satellite orbits.

  • Achievements: Physics represents significant human intellectual achievement in understanding nature.

Branches of Physics

Classical Physics

  1. Mechanics: Study of motion and related concepts of force and energy.

    • Subfields: Kinematics (describes motion) and Dynamics (explains forces behind motion).

  2. Thermodynamics

  3. Optics

  4. Electromagnetism

Modern Physics

  1. Relativity

  2. Quantum Mechanics

Key Concepts in Mechanics

Kinematics

  • Focus on HOW objects move, ignoring external forces (except gravitational effects).

  • Classifications of Motion:

    • Uniform Motion: Constant speed in a straight line.

    • Accelerated Motion: Change in velocity over time.

Dynamics

  • Explains WHY objects move as they do, incorporating forces into the study of motion.

Motion Classifications

Types of Motion

  1. Uniform Motion: Constant speed over time.

  2. Uniformly Accelerated Motion (UAM): Constant acceleration leads to linear displacement.

  3. Projectile Motion: Motion of an object thrown into the air, influenced by gravity.

  4. Free Fall: Describes acceleration due to gravity, neglecting air resistance.

Frame of Reference

  • Definition: Measurement of position, distance, or speed requires a reference point.

  • Examples: Specifying direction (North, South, etc.) or using reference frames like train motion.

Scalars vs. Vectors

  • Scalar Quantities: Have magnitude only (e.g., distance, speed).

  • Vector Quantities: Have both magnitude and direction (e.g., displacement, velocity).

  • Displacement vs. Distance:

    • Distance: Total path length travelled, scalar quantity.

    • Displacement: Vector change in position, difference between final and initial position.

Speed and Velocity

  • Speed: Scalar quantity indicating how fast an object moves.

    • Average speed formula:

      • [ ext{Average Speed} = rac{ ext{Total Distance}}{ ext{Time}} ]

  • Velocity: Vector quantity, including direction, representing the rate of change of displacement.

    • Average velocity formula:

      • [ ext{Average Velocity} = rac{ ext{Displacement}}{ ext{Time}} ]

Acceleration

  • Definition: Change in velocity per unit of time.

  • Average Acceleration Formula:

    • [ ext{Average Acceleration} = rac{ ext{Change in Velocity}}{ ext{Time}} ]

  • Can describe increasing speed (positive acceleration) or slowing down (negative acceleration or deceleration).

Kinematic Equations for Uniformly Accelerated Motion

Main Equations

  1. [ v_f = v_i + a t ] (Final Velocity)

  2. [ riangle d = v_i t + rac{1}{2} a t^2 ] (Displacement)

  3. [ v_f^2 = v_i^2 + 2a riangle d ] (Final velocity squared relation)

Example Problems

Problem 1: Average Velocity

  • Given data:

    • Initial: 50.0 m

    • Final: 30.5 m

    • Time: 3.0 s

  • Solution for average velocity: [ v_{avg} = rac{df - di}{ riangle t} = rac{30.5 - 50.0}{3.0} = -6.5 m/s ]

    • Answer: -6.5 m/s (West)

Problem 2: Displacement Calculation

  • Given data:

    • Distance = 60m

    • Returned to starting point.

  • Solution:

    • Total distance = 120m, displacement = 0m.

Problem on Acceleration

  • Given:

    • Initial Velocity (vi): 0 m/s

    • Final Velocity (vf): 75 km/h

    • Time (t): 5.0 s

  • Calculation of average acceleration:

    • Convert unit: (75 ext{ km/h} = 20.83 ext{ m/s} )

    • [ a = rac{vf - vi}{tf - ti} = rac{20.83 - 0}{5.0} = 4.17 m/s^2 ]

Final Thoughts

  • Physics involves key principles that help explain both basic phenomena and complex interactions in our world. Understanding these foundational subjects equips students to tackle practical applications in engineering and technology.