Describing Motion Around Us - Vocabulary Flashcards

This set of flashcards covers vocabulary and key physical quantities related to linear and circular motion, including definitions and formulas for speed, velocity, displacement, and acceleration.

Linear Motion

The simplest kind of motion, occurring when an object moves in a straight line.

Position

The distance and direction of an object with respect to a reference point at any instant of time.

Reference Point

A fixed point used to specify the position of an object.

Origin (O)

A specific reference point marked on a straight line used to measure positions, typically starting at $0\,m$.

Motion

When the position of an object with respect to a reference point changes with time.

Rest

When the position of an object with respect to a reference point does not change with time.

Distance Travelled

The total path length covered by an object between starting and stopping positions.

Displacement

The net change in the position of an object between two given instants of time.

Magnitude

The numerical value (with units) of a physical quantity.

Scalars

Physical quantities which can be specified by just their numerical value.

Vectors

Physical quantities which require specifying both magnitude and direction.

Instant of time

A single reading of a clock at a given point of time.

Time interval

The time duration between two instants of time, or the difference between two readings of a clock.

Average Speed

The total distance travelled divided by the time interval during which the distance was covered ($\text{average speed} = \frac{\text{total distance travelled}}{\text{time interval}}$).

Uniform Motion

Motion in a straight line where an object travels equal distances in equal intervals of time at a constant speed.

Non-uniform Motion

Motion in a straight line where an object travels unequal distances in equal intervals of time, involving increasing or decreasing speeds.

Average Velocity

The change in position or displacement divided by the time interval in which the change occurred ($\text{average velocity} = \frac{\text{displacement}}{\text{time interval}}$).

Rate of Change

The ratio of change in one quantity to the corresponding change in time.

Instantaneous Velocity

The velocity of an object at a particular instant of time, approached as the time interval becomes infinitesimally small.

Average Acceleration

The change in velocity divided by the time interval ($\text{average acceleration} = \frac{\text{final velocity} - \text{initial velocity}}{\text{time interval}}$).

Acceleration due to gravitational force (g)

A constant acceleration experienced by an object falling vertically toward Earth, equal to $9.8\,m\,s^{-2}$.

Slope of a graph

The steepness of a line representing the rate of change of the quantity on the Y-axis with respect to the quantity on the X-axis.

Kinematic Equations

A set of equations including $v = u + at$, $s = ut + \frac{1}{2}at^2$, and $v^2 = u^2 + 2as$ that describe motion with constant acceleration.

Circular Motion

Motion that occurs when an object moves along a circular path.

Uniform Circular Motion

Motion where an object moves in a circular path with constant (uniform) speed.

Tangent

A straight line that meets a circle at one and only one point, indicating the direction of velocity in uniform circular motion.