Physics 1000 - Introduction to Physical Standards

Introduction to Physics

• Physics involves studying the physical world by identifying patterns and predicting future behaviors.
• The discipline relies on experimentation to establish scientific laws.

Scientific Laws

• Scientific laws are universally accepted principles from consistent experimental results.
• Terms like scientific law, physical law, and law of nature are interchangeable.
• No experimental result can definitively prove an idea; they can only disprove it.
• A scientific law must be testable, allowing for predictions that can potentially be disproven.

Physical Standards and Units

• Common reference frames are essential for measuring quantities like distance and time.
• Units are established standards to ensure consistent measurements.
• Various measurement systems exist, such as the metric (SI) and US systems; SI units will primarily be used in this course.

Area Unit Comparison (US/SI)

• Area is calculated as the product of two distances.
• Example of an acre: defined as 66 feet by 660 feet, totaling 39,600 square feet.
• Example of a square kilometer: one kilometer by one kilometer equating to one million square meters.

Units of Measurement

• Length: Meter (m), Foot (ft) - Conversion: Multiply by 3.281 (SI to US), Divide by 3.281 (US to SI).
• Mass: Kilogram (kg), Pound (lb) - Conversion: Multiply by 2.205 (SI to US), Divide by 2.205 (US to SI).
• Time: Second (s) - Same unit in both systems.
• Force: Newton (N), Pound force (lbf) - Conversion: Divide by 4.448 (SI to US), Multiply by 4.448 (US to SI).
• Energy: Joule (J), Foot-pound (ft*lb) - Conversion: Divide by 1.356 (SI to US), Multiply by 1.356 (US to SI).
• Current: Ampere (A) - Same unit in both systems.
• Temperature: Kelvin (K), Degree Fahrenheit (°F) - Different systems.

Metric Prefixes

• Standard prefixes indicate various powers of ten:
  • Peta- (P, 10^15), Tera- (T, 10^12), Giga- (G, 10^9), Mega- (M, 10^6), Kilo- (k, 10^3).
  • Common subdivisions: centi- (c, 10^-2), milli- (m, 10^-3), micro- (μ, 10^-6), nano- (n, 10^-9), pico- (p, 10^-12), femto- (f, 10^-15).

Scientific Notation

• A method for succinctly expressing very large or small numbers.
• Formulated as ( a \times 10^n ), where ( n ) is an integer.
• Significant workplace in comparing orders of magnitude, indicating if two numbers' ratio is between 1/10 and 10.
• Illustrative example: 3,000,000 (30 x ( 10^6 )) is five orders of magnitude apart from 30.

Homework

• Read Chapter 1 and prepare answers for questions: 3, 5, 9, 10, 18, 19, 23, 26, 27, 29.