Term1_Portions(Revision material)

Definition: Density is a measure of how much mass is contained in a given volume, indicating how "compact" a material is.
Formula:
- ρ = m/V
- Where:
  - ρ = density (kg/m³)
  - m = mass (kg)
  - V = volume (m³)
Explanation: Different materials have varying densities due to differences in atomic structures. For example, metals have higher densities than wood due to closer elemental packing.
Applications:
- Identifying materials based on density; pure gold has a specific density.
- Predicting if an object will float or sink in water; objects less dense than water will float.

Definition: A force is a push or pull that can affect an object's motion, stopping ability, or shape change.
Types of Forces:
- Contact Forces: Occur when two objects are in physical contact.
  - Examples:
    - Friction: Resists motion when two surfaces slide.
    - Tension: The pulling force transmitted through a rope, string, or cable.
    - Normal Force: The supporting force exerted by a surface on an object in contact.
- Non-Contact Forces: Act over a distance without physical contact.
  - Examples:
    - Gravitational Force: Attraction between two masses.
    - Electrostatic Force: Interaction between charged particles.
    - Magnetic Force: Force from a magnetic field on moving charges or materials.

Balanced Forces: Forces are equal in size but opposite in direction, canceling each other, maintaining an object's state of rest or constant velocity.
Unbalanced Forces: One force is greater, causing a change in motion (acceleration/deceleration).
Resultant Force: The combined effect of all forces on an object.
- Example: A box with a 10N force to the right and a 6N left results in a 4N force to the right.
Formula:
- F = ma
  - Where:
    - F = force (N)
    - m = mass (kg)
    - a = acceleration (m/s²)

Explanation: The formula F = ma shows that force affects mass and resulting acceleration directly. Lighter objects accelerate more under the same force than heavier ones.
Examples:
- Pushing a ball requires less force than pushing a car to achieve the same acceleration.
- A loaded truck needs more force to accelerate than an empty truck.
Applications:
- Used in vehicle dynamics, rocket launches, and calculating gravitational effects. Engineers apply F = ma in designing structures and machines.

Definition: The upward force exerted by a fluid to oppose gravity and enable objects to float.
Archimedes’ Principle: States that the buoyant force equals the weight of the fluid displaced by an object submerged in the fluid.
Explanation: If the object's weight is less than the buoyant force, it floats; if greater, it sinks.
Applications:
- Ship design (to float by displacing adequate water) and submarines (adjust buoyancy through water control).

Formula:
- Fb = ρ⋅V⋅g
  - Where:
    - Fb = buoyant force (N)
    - ρ = fluid density (kg/m³)
    - V = volume of displaced fluid (m³)
    - g = gravitational strength (9.8 N/kg)

Explanation:
- An object displaces fluid, and the buoyant force equals the weight of that displaced fluid. An object's ability to float or sink relies on the balance between buoyant force and its weight:
  - Buoyant force > weight: object floats.
  - Buoyant force < weight: object sinks.
Applications:
- Ships and Boats: Designed to displace enough water to float.
- Submarines: Adjust buoyancy by changing ballast water amount.
- Hydrometers: Measure fluid density based on submersion depth.

Definition: Force exerted per unit area on a surface.
Formula:
- P = F/A
  - Where:
    - P = pressure (Pa)
    - F = force (N)
    - A = area (m²)
Explanation: Pressure increases with higher force or smaller area.
Applications: High heels create more pressure on the ground than flat shoes due to reduced contact area.

Definition: In fluids, pressure increases with depth due to the weight of fluid above.
Formula:
- P = ρ⋅g⋅h
  - Where:
    - ρ = fluid density (kg/m³)
    - g = gravitational field strength (9.8 N/kg)
    - h = depth (m)
Explanation: Deep-sea creatures face significant pressure from their environment.
Applications: Considerations for hydraulic lifts, dams, and understanding underwater pressures.

Types of Effects:
- Starting Motion: Initiates movement for a stationary object.
- Stopping Motion: Stops a moving object (e.g., car brakes).
- Changing Direction: Alters direction of an object (e.g., steering vehicle).
- Changing Shape: Forces can deform objects (e.g., compressing a spring).
Explanation: Forces influence an object’s speed, direction, and shape according to Newton’s laws.

Scalars: Quantities described only by magnitude.
- Examples: Speed, mass, time, temperature.
Vectors: Quantities defined by both magnitude and direction.
- Examples: Velocity, displacement, acceleration, force.
Representation: Vectors depicted as arrows; length indicates magnitude, direction indicated by the arrowhead.

Distance: Total path length covered, scalar quantity.
Displacement: Straight-line distance between start and end points, accounting for direction.
- Example: Walking in a square results in a large distance but zero displacement if the start and end points coincide.

Equations:
- v = u + at
- S = ut + 1/2 at²
- v² = u² + 2aS
- S = ut + 1/2 at
- Variables:
  - u = initial velocity
  - v = final velocity
  - a = acceleration
  - t = time
  - S = displacement

Types:
- Distance-Time Graphs: Illustrates speed.
- Velocity-Time Graphs: Shows acceleration.
- Acceleration-Time Graphs: Indicates changes in velocity.

Definition: Constant speed achieved when air resistance equals gravitational force on a falling object.
Factors: Mass, surface area, and air density influence terminal velocity.