Physics: Motion, Vectors, and Scalars

Vocabulary flashcards covering the fundamental concepts of motion, including scalars, vectors, speed, velocity, acceleration, and the dynamics of freefall and terminal velocity.

Scalar quantity

A quantity that has magnitude (size) only, such as distance, speed, time, mass, energy, and temperature.

Vector quantity

A quantity that has both magnitude and direction, such as force, weight, velocity, acceleration, momentum, electric field strength, and gravitational field strength.

Distance ($s$)

A scalar quantity that represents the total path traveled with magnitude only.

Displacement ($s$)

A vector quantity that represents the change in position with both magnitude and direction.

Speed

The distance travelled per unit time, calculated as $v = \frac{s}{t}$, measured in $m/s$ or $m\,s^{-1}$.

Average speed

The total distance travelled divided by the total time taken.

Velocity

The distance travelled per unit time in a given direction, or displacement per unit time.

Acceleration

The change in velocity per unit time, measured in $m/s^2$ or $m\,s^{-2}$.

Deceleration

Negative acceleration that occurs when an object is slowing down.

Constant acceleration

When an object accelerates at a steady rate, represented on a speed-time graph as a non-horizontal straight line.

Acceleration of freefall

The acceleration of an object falling in the absence of air resistance, which is approximately $9.8\,m\,s^{-2}$ or $9.81\,m\,s^{-2}$ near Earth's surface.

Gravitational field strength ($g$)

The value used to calculate the weight of an object using its mass, where $W = mg$, also representing the acceleration of freefall.

Weight

The force of gravity on an object with mass, distinct from mass and calculated as the product of mass and gravitational field strength.

Air resistance

A frictional force (or drag) produced by collisions with air particles that acts in the opposite direction of motion and increases as speed increases.

Terminal velocity

The constant speed reached by a falling object when the upward force of air resistance eventually grows large enough to balance the downward weight force, resulting in zero acceleration.

Gradient of a distance-time graph

A calculation representing the magnitude of the speed of the moving object.

Gradient of a speed-time graph

A calculation representing the magnitude of the acceleration of the moving object.

Area under a speed-time graph

A calculation used to determine the total distance travelled by an object.