Describing Motion Around Us

A set of vocabulary flashcards covering the fundamental concepts of kinematics, including linear and circular motion, scalars and vectors, and the graphical and mathematical description of motion.

Linear motion

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

Uniform circular motion

Motion that occurs when an object moves in a circular path with constant speed.

Reference point

A fixed point specified to describe the distance and direction of an object's position.

Motion

The state of an object when its position changes with respect to a reference point over time.

Rest

The state of an object when its position does not change with respect to a reference point with time.

Origin 'O'

The reference point on a straight line path from which positions are measured.

Distance travelled

The total length of the path covered by an object, requiring only a numerical value and units.

Displacement

The net change in the position of an object between two given instants of time, requiring both magnitude and direction.

Magnitude

The numerical value of a physical quantity, including its units.

Scalars

Physical quantities that can be specified by just their numerical value, such as distance or speed.

Vectors

Physical quantities that require specifying both their magnitude and direction, such as displacement or velocity.

Average speed

The total distance travelled divided by the time interval during which the distance is covered.

Uniform motion in a straight line

A type of motion where an object travels equal distances in equal intervals of time along a straight path.

Non-uniform motion in a straight line

A type of motion where an object travels unequal distances in equal intervals of time.

Yojana

A unit of distance used in ancient India, mentioned in the mathematical text Ganitakaumudi.

Average velocity

The change in position, or displacement, divided by the time interval in which the change occurs.

Rate of change

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

$$m\,s^{-1}$$

The SI unit of both average speed and average velocity, representing metres per second.

Instantaneous velocity

The velocity of an object at a particular instant of time, often simply referred to as velocity.

Average acceleration

The change in velocity of an object divided by the time interval over which the change occurs.

$$m\,s^{-2}$$

The SI unit of average acceleration, representing metres per second squared.

Acceleration due to gravitational force ($g$)

The constant acceleration of an object falling vertically toward Earth, measured at approximately $9.8\,m\,s^{-2}$.

Instantaneous acceleration

The value of an object's acceleration at a specific instant in time.

Slope of a graph

A measure of the steepness of a line that describes the rate of change of the y-axis quantity with respect to the x-axis quantity.

Velocity-time graph

A graphical representation used to determine acceleration from the slope and displacement from the area enclosed.

Kinematic equations

A set of mathematical descriptions, such as $v = u + at$ and $v^2 = u^2 + 2as$, used for motion with constant acceleration.

Tangent

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

Motion in a plane

Also known as motion in two dimensions, which includes patterns like a kicked ball's path or circular orbits.

Motion in space

Motion in three dimensions, such as a bird flying in the sky or an aircraft moving through air.

$$v = u + at$$

The kinematic equation that relates final velocity ($v$), initial velocity ($u$), constant acceleration ($a$), and time ($t$).