Measurement and Scientific Investigation

Vocabulary flashcards reviewing base and derived physical quantities, measurement units, scalars, vectors, and graph interpretations from Chapter 1 Measurement.

Physical Quantity

A quantity that can be measured by measuring instruments, stated in terms of magnitude and unit.

Metre Rule

A measuring instrument used to measure length.

Thermometer

A measuring instrument used to measure temperature.

Ammeter

A measuring instrument used to measure electric current.

Stopwatch

A measuring instrument used to measure time.

Voltmeter

A measuring instrument used to measure voltage.

Weighing Scale

A measuring instrument used to measure weight.

Base Quantities

Physical quantities that cannot be defined in terms of other quantities.

Metre ($m$)

The S.I. unit for the base quantity length ($l$).

Kilogram ($kg$)

The S.I. unit for the base quantity mass ($m$).

Second ($s$)

The S.I. unit for the base quantity time ($t$).

Kelvin ($K$)

The S.I. unit for the base quantity temperature ($T$).

Ampere ($A$)

The S.I. unit for the base quantity electric current ($I$).

Candela ($cd$)

The S.I. unit for the base quantity luminous intensity ($I_v$).

Mole ($mol$)

The S.I. unit for the base quantity amount of substance ($n$).

Derived Quantities

Quantities that are defined in terms of base quantities and stated in derived units.

Area

A derived quantity calculated as $\text{length} \times \text{width}$ ($l \times l$) with the derived S.I. unit $m^2$.

Electric Charge

A derived quantity calculated as $\text{current} \times \text{time}$ ($I t$) with the derived S.I. unit $A balance s$ ($A s$).

Velocity

A derived quantity calculated as $\frac{\text{displacement}}{\text{time}}$ ($\frac{l}{t}$) with the derived S.I. unit $m s^{-1}$.

Density

A derived quantity calculated as $\frac{\text{mass}}{\text{volume}} = \frac{\text{mass}}{\text{length} \times \text{width} \times \text{height}}$ ($\frac{m}{l \times l \times l}$) with the derived S.I. unit $kg m^{-3}$.

Acceleration

A derived quantity calculated as $\frac{\text{velocity}}{\text{time}} = \frac{\text{displacement}}{\text{time} \times \text{time}}$ ($\frac{l}{t^2}$) with the derived S.I. unit $m s^{-2}$.

Force

A derived quantity calculated as $\text{mass} \times \text{acceleration} = \text{mass} \times \frac{\text{displacement}}{\text{time} \times \text{time}}$ ($\frac{m l}{t^2}$) with the derived S.I. unit $kg m s^{-2}$ ($1 N = 1 kg m s^{-2}$).

Work

A derived quantity calculated as $\text{force} \times \text{distance} = \text{mass} \times \frac{\text{distance}}{\text{time} \times \text{time}} \times \text{distance}$ ($\frac{m l^2}{t^2}$) with the derived S.I. unit $kg m^2 s^{-2}$ ($1 J = 1 kg m^2 s^{-2}$).

Scalar Quantities

Physical quantities that have magnitude only (e.g., distance, time, density, speed, temperature, volume, work, power, energy, area).

Vector Quantities

Physical quantities that have both magnitude and direction (e.g., displacement, velocity, force, acceleration, momentum).

Direct Proportionality Graph

A graph featuring a straight line passing through the origin, indicating $y$ is directly proportional to $x$.

Linear Increase Graph

A graph featuring a straight line that does not pass through the origin and has a positive gradient, indicating $y$ increases linearly with $x$.

Linear Decrease Graph

A graph featuring a straight line that does not pass through the origin and has a negative gradient, indicating $y$ decreases linearly with $x$.

Inverse Proportionality Graph

A graph where $y$ is inversely proportional to $x$ (or $y$ is directly proportional to $\frac{1}{x}$), represented as a curve or a straight line of $y$ against $\frac{1}{x}$ passing through the origin.

Gradient of a Graph

Calculated using the formula $m = \frac{y_2 - y_1}{x_2 - x_1}$ to determine the physical relationship represented by the slope.

Interpolation

The technique of using a graph to determine the value of a quantity (finding $y$ when $x$ is given or vice versa) within the range of measured data points.

Extrapolation Line

Extending the line of a graph beyond measured data to make predictions or estimate unknown values.

Area Under the Graph

The calculated region beneath a plotted graph used to determine specific physical quantities represented by that area.