Chapter 1 paterns of Motion and Equilibrium

Lecture covers key concepts:

Classification of Motion:
- Natural Motion: Straight up or straight down.
- Violent Motion: Imposed motion due to external push or pull.

Demolished Aristotelian Assertions: In absence of a force, objects in motion remain in motion indefinitely.
Inertia: Resistance to Change.
- Example: Leaning Tower of Pisa experiment with dropped objects.
- Galileo demonstrated that all objects fall at the same rate without air resistance.
- Horizontal Motion: In absence of friction, no force is necessary to keep a moving object in motion.
- Experiments with Inclined Planes: Balls rolling down and up inclined planes demonstrating inertia — returning to original height.

Definition of Mass: Quantity of matter that composes an object.
- Greater mass results in greater inertia, and vice versa.
Weight: Amount of gravitational pull on an object; proportional to mass.
- Relation: Twice the mass = twice the weight.
Mass vs. Volume:
- Mass: How much matter is contained.
- Volume: How much space an object occupies.

Units of Measurement for Mass: Kilogram (kg) is the standard; 1 kg = 10 Newton on Earth.
- Mass remains constant regardless of location (e.g., Moon).

Definition: Net force combines all forces acting on an object; it is crucial for understanding how motion changes.
- It determines changes in an object’s state of motion by indicating whether or not an object will accelerate.
Vector Representation:
- Force vector: Magnitude and direction represented as an arrow.
- Resultant: Net result of combined vectors (forces).
- To calculate net force, one must sum all forces acting on an object considering their directions, where forces acting in opposite directions subtract from each other.
Gravitational Pull:
- Gravitational pull is the attractive force exerted by the Earth (or another massive body) on an object, pulling it towards the center.
- This force is calculated using the formula: Weight (W) = mass (m) × gravitational acceleration (g).
- On Earth, g is approximately 9.8 m/s², meaning for every kilogram of mass, there is a gravitational pull of about 9.8 Newtons.
- The gravitational pull is a constant force acting on all objects, contributing significantly to their net force when combined with other forces.

Definition: State of no change; rest or constant velocity indicates equilibrium.
Mathematical Notation: ΣF = 0 (vector sum of forces equals zero).
Conditions: An object can only be in equilibrium under multiple forces (net force cannot be zero under a single force alone).

Definition: Normal force acting upward against gravity; it is equal and opposite to the gravitational force on an object resting on a surface.

Condition: Object moving at constant velocity; forces cancel to zero.
Friction: Resistive force acting opposite to motion, can occur in fluids, air, or solid surfaces.

Speed: Distance covered per unit time.
- Formula: Speed = Distance / Time.
Velocity: Speed with a direction specified.
- Average vs. Instantaneous Speed: Average speed is total distance/time.
- Instantaneous speed is at a specific moment.

Definition: Rate at which velocity changes over time.
- Formula: Acceleration = (Change in Velocity) / Time Interval.
Free Fall: When falling under the influence of gravity alone, experiencing gravitational acceleration (g = 9.8 m/s²).