Measurement and Vectors - GENPHY 1 Topic 1

Vocabulary flashcards covering Measurement and Vectors topics from GENPHY 1 Topic 1.

Measurement

Process of assigning quantities to objects or events.

Physical quantity

Any quantity used to describe a physical phenomenon (e.g., height, weight, age, brightness, pitch).

Unit

A reference standard that defines a quantity and gives it a numerical value.

International System of Units (SI)

Global system of units agreed by scientists (CGPM, 1968) for consistent measurement, based on the metric system.

Meter (m)

SI base unit of length.

Kilogram (kg)

SI base unit of mass.

Second (s)

SI base unit of time.

Kelvin (K)

SI base unit of temperature.

Ampere (A)

SI base unit of electric current.

Candela (cd)

SI base unit of luminous intensity.

Mole (mol)

SI base unit of amount of substance.

Prefix

A multiplier placed before a base unit to scale it by powers of ten (e.g., kilo = 10^3).</termimplies

Prefix: Tera (T)

10^12.

Prefix: Giga (G)

10^9.

Prefix: Mega (M)

10^6.

Prefix: Kilo (k)

10^3.

Prefix: Deci (d)

10^-1.

Prefix: Centi (c)

10^-2.

Prefix: Milli (m)

10^-3.

Prefix: Micro (μ)

10^-6.

Prefix: Nano (n)

10^-9.

Prefix: Pico (p)

10^-12.

Prefix: Deca (da)

10^1.

Scientific notation

A concise form to write numbers as a coefficient times 10^exponent (e.g., 1,000,000 = 10^6; 0.000000000001 = 10^-12).

Derived units

Units derived from base SI units (e.g., Newton for force, Pascal for pressure, Hertz for frequency, Coulomb for charge, Ohm for resistance, Joule for energy).

Uncertainty

The maximum expected difference between a measured value and the true value; depends on the measurement method.

Accuracy

How close a measurement is to the true value.

Precision

How close a set of measurements are to each other.

Random error

Unpredictable fluctuations in measurements that affect precision.

Systematic error

A consistent bias that shifts measurements away from the true value.

Scalar quantity

A quantity described by magnitude only (e.g., volume, density, speed, mass, time).

Vector quantity

A quantity described by both magnitude and direction (e.g., displacement, velocity, force, momentum, weight, current).

Vector

A quantity with both magnitude and direction; often represented graphically with arrows.

Displacement

A vector representing a change in position.

Magnitude

The length or size of a vector.

Direction

The orientation of a vector.

Resultant

The vector sum of two or more vectors.

Head-to-tail method

Graphical method to add vectors by placing the tail of one vector at the head of the previous one; the resultant connects the initial tail to the final head.

Cartesian coordinate system

A 2D plane with perpendicular x and y axes used to specify vector components and directions.

Component form

Representing a vector as the sum of its x- and y-components (Ax, Ay).

Magnitude-Direction form

Expressing a vector by its magnitude and direction (e.g., A = 400 km, 45° North of East).

Pythagorean theorem (for vectors)

For perpendicular components, resultant magnitude R = sqrt(Ax^2 + Ay^2).

1D vector addition

When vectors are parallel, add magnitudes; when antiparallel, subtract magnitudes to obtain the resultant.

Velocity vs Speed

Speed is the rate of motion (scalar); velocity is speed with a specified direction (vector).

Quadrants in Cartesian coordinates

Q1: (+x, +y); Q2: (-x, +y); Q3: (-x, -y); Q4: (+x, -y).