Describing Motion Around Us - Vocabulary

Key vocabulary terms and definitions covering straight-line motion, position, displacement, average speed, and average velocity from the transcript.

Linear motion

The motion of an object when it moves in a straight line.

Reference point

A fixed point with respect to which the position or motion of an object is described.

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, which is the duration between two readings of a clock.

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 the direction and magnitude.

Physical quantity

A property of a material or system that can be measured and quantified.

Average speed

The total distance travelled divided by the time interval during which this distance is covered, calculated as $\text{average speed} = \frac{\text{total distance travelled}}{\text{time interval}}$.

Uniform motion in a straight line

Motion in which an object moving in a straight line travels equal distances in equal intervals of time for all possible choices of time intervals.

Non-uniform motion in a straight line

Motion in which an object moving in a straight line travels unequal distances in equal intervals of time.

Average velocity

The change in position (or displacement) divided by the time interval in which the change occurs, expressed as $v_{av} = \frac{s}{t}$.

Rate of change

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

Yojana

A unit of distance used in ancient India.