Physics Measurement and Motion Concepts

Study Notes

Units of Measurement:
- Length: meter (m)
- Mass: kilogram (kg)
- Time: second (s)
Measuring Instruments:
- Ruler: for measuring length (cm, m)
- Balance: for measuring mass (g, kg)
- Stopwatch: for measuring time (s)
Precision and Accuracy:
- Precision: consistency of repeated measurements
- Accuracy: closeness of a measurement to the true value
Significant Figures:
- Important for conveying precision in measurements
- Rules for determining significant figures (non-zero digits, zeros between significant digits, etc.)

Types of Motion:
- Linear: straight line motion
- Circular: movement along a circular path
- Oscillatory: back and forth motion (e.g., pendulum)
Distance vs. Displacement:
- Distance: total path length traveled (scalar)
- Displacement: straight line from start to end point (vector)
Speed and Velocity:
- Speed: distance traveled per unit time (scalar)
- Velocity: displacement per unit time (vector)
Acceleration:
- Change in velocity over time (m/s²)
- Can be positive (increasing speed) or negative (deceleration)

Force:
- A push or pull acting on an object (measured in Newtons, N)
- Can cause a change in motion (acceleration)
Types of Forces:
- Contact forces: friction, tension, normal force
- Non-contact forces: gravitational, magnetic, electrostatic
Newton's Laws of Motion:
- First Law: An object at rest stays at rest; an object in motion stays in motion unless acted upon by a net external force (inertia).
- Second Law: F = ma (force equals mass times acceleration); describes how the velocity of an object changes when it is subjected to external forces.
- Third Law: For every action, there is an equal and opposite reaction.
Weight vs. Mass:
- Mass: amount of matter in an object (kg)
- Weight: force of gravity acting on an object (W = mg; g ≈ 9.81 m/s² on Earth)

Units of Measurement define standard quantities for various physical properties: length in meters (m), mass in kilograms (kg), and time in seconds (s).
Measuring Instruments include rulers for length (measure in centimeters or meters), balances for mass (measure in grams or kilograms), and stopwatches for time (measure in seconds).
Precision and Accuracy are crucial for reliable measurements: precision refers to the consistency of repeated measurements, while accuracy indicates how close a measurement is to the true value.
Significant Figures are used to communicate the precision of measurements, with specific rules for determining them based on non-zero digits and zeros between significant digits.

Types of Motion include: linear (straight line), circular (along a circular path), and oscillatory (back and forth, like a pendulum).
Distance vs. Displacement: distance measures the total path length (scalar quantity), whereas displacement records the straight line from start to end (vector quantity).
Speed and Velocity are related but distinct concepts: speed measures how much distance is traveled over time (scalar), while velocity includes direction, measuring displacement over time (vector).
Acceleration quantifies the change in velocity per time unit, expressed in meters per second squared (m/s²), and can be either positive (speeding up) or negative (deceleration).

Force is defined as a push or pull on an object, measured in Newtons (N), and can induce a change in an object's motion.
Types of Forces are categorized as contact forces (such as friction, tension, and normal force) and non-contact forces (including gravitational, magnetic, and electrostatic).
Newton's Laws of Motion outline fundamental principles:
- First Law (Inertia): Objects remain at rest or in uniform motion unless acted upon by an external force.
- Second Law: The relationship between force, mass, and acceleration is given by F = ma.
- Third Law: Every action has an equal and opposite reaction.
Weight vs. Mass: mass quantifies the amount of matter in an object (in kilograms), while weight is the gravitational force acting on that mass, calculated as W = mg, with gravitational acceleration (g) on Earth approximately 9.81 m/s².