Physics 1020 - Chapter 1: Measurements and Units (General Physics)

Vocabulary flashcards covering key terms from Chapter 1: Measurements, SI units, prefixes, scientific notation, significant figures, and dimensional analysis.

Physics

Natural science involving the study of the universe.

Model

A simplified representation or mental picture used to understand phenomena.

Law

A brief description of how nature behaves in a broad set of circumstances.

Principle

Similar to a law but applies to a narrower range of phenomena.

Theory

A broader, more detailed explanation that can give testable predictions.

Measurement

Process of describing natural phenomena by obtaining a magnitude and a unit for a physical quantity.

Physical quantity

A property that can be measured, such as length, mass, time, or temperature.

Quantity

A property that can be measured; expressed as a numerical value (magnitude) and a unit.

Unit

A standard used to express the magnitude of a physical quantity.

SI units

System of International Units with seven base units and derived units; adopted globally.

Base quantity

A fundamental quantity in SI that is not derived from others (e.g., length, mass, time).

Base unit

The standard unit for a base quantity (e.g., meter for length).

Seven base quantities

Length, Mass, Time, Electric current, Temperature, Amount of substance, Luminous intensity.

Meter (m)

SI base unit of length; defined by the distance light travels in vacuum in 1/299,792,458 s.

Kilogram (kg)

SI base unit of mass; defined by the mass of a specific platinum–iridium alloy cylinder.

Second (s)

SI base unit of time; defined by 9,192,631,700 oscillations of the cesium-133 atom.

Ampere (A)

SI base unit of electric current.

Kelvin (K)

SI base unit of thermodynamic temperature.

Mole (mol)

SI base unit of amount of substance.

Candela (cd)

SI base unit of luminous intensity.

Derived quantity

Quantity formed by combining base quantities (e.g., N, m/s, m^2).

Length unit (meter)

Unit of length in SI; defined as the distance light travels in vacuum in 1/299,792,458 s.

Mass unit (kilogram)

SI base unit of mass; defined by a platinum–iridium cylinder.

Time unit (second)

SI base unit of time; defined by cesium-133 oscillations.

Electric current unit (ampere)

SI base unit for electric current.

Temperature unit (kelvin)

SI base unit for temperature.

Amount of substance unit (mole)

SI base unit for amount of substance.

Luminous intensity unit (candela)

SI base unit for luminous intensity.

Prefix

A symbol that denotes a power-of-ten scale factor for units.

Tera (T)

Prefix meaning 10^12.

Giga (G)

Prefix meaning 10^9.

Mega (M)

Prefix meaning 10^6.

Kilo (k)

Prefix meaning 10^3.

Deci (d)

Prefix meaning 10^-1 (0.1).

Centi (c)

Prefix meaning 10^-2 (0.01).

Milli (m)

Prefix meaning 10^-3 (0.001).

Micro (µ)

Prefix meaning 10^-6 (0.000001).

Nano (n)

Prefix meaning 10^-9 (0.000000001).

Pico (p)

Prefix meaning 10^-12 (0.000000000001).

Femto (f)

Prefix meaning 10^-15 (0.000000000000001).

Scientific notation

A × 10^n where a is between 1 and 10 (inclusive of 1, exclusive of 10) and n is an integer.

Coefficient

The A in scientific notation; a number between 1 and 10.

Exponent

The n in scientific notation; an integer representing the power of 10.

Significant figures

Digits in a measurement that carry meaningful precision.

Significant figure rules (overview)

• Zeros between nonzero digits are significant; - Leading zeros are not significant; - Trailing zeros after decimal are significant; - Trailing zeros without decimal are not significant; - Nonzero digits are significant; - Zeros with powers of 10 can be significant.

Dimensional analysis

Method to analyze physical quantities by their dimensions to check consistency and derive units.

Dimension

A fundamental type of quantity expressed in base dimensions like [L], [M], [T].

[L]

Dimension of length.

[M]

Dimension of mass.

[T]

Dimension of time.

Displacement dimension

Displacement has dimension [L].

Speed dimension

Speed has dimension [L][T]^-1.

Area dimension

Area has dimension [L]^2.

Kinetic energy unit

Unit for KE is kg·m^2/s^2 (joule).

F = ma unit

Force unit: kg·m/s^2 (newton).

G (gravitational constant) dimension

G has dimensions [L]^3[M]^-1[T]^-2.

Braking distance dimension example

Distance d with velocity v has dimension [L] (dimensionally consistent).