Basic Physical Quantities and Laws (Grades 7–9)

Vocabulary flashcards covering core physics formulas, quantities, and SI units for Grades 7 to 9 based on the provided Lithuanian physics reference sheet.

Density of a Substance

The mass per unit volume of a material, given by formula $\rho = \frac{m}{V}$ and measured in $1\,\text{kg/m}^3$.

Distance Traveled in Uniform Motion

The distance covered by a body moving at a constant speed, given by formula $s = vt$ and measured in $1\,\text{m}$.

Uniform Speed

The rate of distance covered per unit time in uniform motion, given by formula $v = \frac{s}{t}$ and measured in $1\,\text{m/s}$.

Acceleration of Uniformly Varied Motion

The rate of change of velocity over time, given by formula $a = \frac{v - v_0}{t}$ and measured in $1\,\text{m/s}^2$.

Period of Oscillation

The time taken for one complete oscillation, given by formula $T = \frac{t}{N}$ and measured in $1\,\text{s}$.

Frequency of Oscillation

The number of oscillations per unit time, given by formula $\nu = \frac{N}{t}$ and measured in $1\,\text{Hz} = 1\,\text{s}^{-1}$.

Wave Propagation Speed

The speed at which a wave travels through a medium, given by formula $v = \frac{\lambda}{T} = \lambda \nu$ and measured in $1\,\text{m/s}$.

Force

An interaction that causes an object to accelerate, given by Newton's second law formula $F = ma$ and measured in $1\,\text{N}$.

Moment of Force

The rotational effect of a force applied to an object, given by formula $M = Fl$ and measured in $1\,\text{N} \cdot \text{m}$.

Mechanical Work

The energy transferred to or from an object via the application of force along a displacement, given by formula $A = Fs$ and measured in $1\,\text{J} = 1\,\text{N} \cdot \text{m}$.

Mechanical Power

The rate at which mechanical work is performed, given by formula $P = \frac{A}{t}$ and measured in $1\,\text{W} = 1\,\text{J/s}$.

Potential Energy

The energy stored in an object due to its position in a gravitational field, given by formula $E_p = mgh$ and measured in $1\,\text{J}$.

Kinetic Energy

The energy possessed by an object due to its motion, given by formula $E_k = \frac{mv^2}{2}$ and measured in $1\,\text{J}$.

Efficiency Coefficient

The ratio of useful work or energy output to total input work or heat, given by formulas $\eta = \frac{A_n}{A_v}$ or $\eta = \frac{A_n}{Q}$.

Pressure of a Solid Body

The force exerted perpendicular to the surface of an object per unit area, given by formula $p = \frac{F}{S}$ and measured in $1\,\text{Pa} = 1\,\text{N/m}^2$.

Hydrostatic Pressure (Liquid Column Pressure)

The pressure exerted by a fluid at equilibrium at a given depth due to the force of gravity, given by formula $p = \rho gh$ and measured in $1\,\text{Pa}$.

Archimedes' Force

The upward buoyant force exerted on a body immersed in a fluid, given by formula $F_A = \rho_s g V$ and measured in $1\,\text{N}$.

Amount of Heat

The heat energy transferred during a temperature change, given by formula $Q = cm(t_2 - t_1)$ and measured in $1\,\text{J}$.

Heat of Combustion of Fuel

The thermal energy released during the complete combustion of a mass of fuel, given by formula $Q = qm$ and measured in $1\,\text{J}$.

Heat of Fusion

The energy required to change a substance from solid to liquid phase (or released upon solidification), given by formula $Q = \lambda m$ and measured in $1\,\text{J}$.

Heat of Vaporization

The energy required to change a substance from liquid to gas phase (or released upon condensation), given by formula $Q = Lm$ and measured in $1\,\text{J}$.

Electric Current Intensity

The rate of electric charge flow through a conductor, given by formula $I = \frac{q}{t}$ and measured in $1\,\text{A}$.

Electric Voltage

The work done per unit charge in moving electric charge between two points, given by formula $U = \frac{A}{q}$ and measured in $1\,\text{V}$.

Electrical Resistance of a Conductor

The measure of opposition to the flow of electric current in a conductor, given by formula $R = \rho \cdot \frac{l}{S}$ and measured in $1\,\Omega$.

Work of Electric Current

The total energy transferred by an electric current, given by formula $A = UIt$ and measured in $1\,\text{J}$.

Electric Power

The rate at which electrical energy is transferred by an electric circuit, given by formula $P = UI$ and measured in $1\,\text{W} = 1\,\text{J/s}$.