Motion Lecture Notes Flashcards

This set of vocabulary flashcards covers the fundamental concepts of motion, including types of motion, scalar and vector quantities, distance, displacement, speed, velocity, acceleration, graphical analysis, equations of motion, and free fall as well as free fall, based on the Class 9 Physics curriculum.

Motion

A state of an object where its position changes with time.

Rest

A state of an object where its position does not change with respect to time or surroundings.

Linear Motion

Motion in a straight line.

Circular Motion

Motion of an object along a circular path.

Oscillatory Motion

Motion where an object moves to and fro repeatedly around a fixed position, such as a pendulum.

Reference Point

A point used to describe the position of an object, which determines if the object is at rest or in motion based on the observer's perspective.

Physical Quantity

A property of a material or system that can be measured, such as mass or length.

Scalar Quantity

Quantities that have magnitude only and do not require direction, such as distance and speed.

Vector Quantity

Quantities that require both magnitude and direction for their description, such as force, displacement, and velocity.

Distance

The total length of the actual path covered by a moving object; it is a scalar quantity and can never be negative.

Displacement

The shortest straight-line distance between the initial and final positions of an object; it is a vector quantity and can be positive, negative, or zero.

Speed

The distance traveled per unit time, calculated as $\text{Speed} = \frac{\text{Distance}}{\text{Time}}$.

Average Speed

The total distance traveled divided by the total time taken to cover that distance: $\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}}$.

Kilometer per hour to Meter per second Conversion

To convert $km/h$ to $m/s$, multiply the value by $\frac{5}{18}$.

Velocity

The displacement of an object per unit time in a given direction: $\text{Velocity} = \frac{\text{Displacement}}{\text{Time}}$.

Average Velocity

The sum of initial velocity ($u$) and final velocity ($v$) divided by $2$, or total displacement divided by total time: $\text{Average Velocity} = \frac{u + v}{2}$.

Acceleration

The rate of change of velocity; calculated as $a = \frac{v - u}{t}$, where $v$ is final velocity, $u$ is initial velocity, and $t$ is time.

SI Unit of Acceleration

The standard unit for acceleration, which is $m/s^2$.

Retardation (Negative Acceleration)

A decrease in velocity with time, denoted with a negative sign in acceleration calculations.

Uniform Motion

Motion where an object maintains a constant velocity, meaning acceleration is zero ($a = 0$).

Non-uniform Motion

Motion where the velocity of an object changes over time, indicating the presence of acceleration.

Slope of Position-Time Graph

Represents the velocity of the object.

Slope of Velocity-Time Graph

Represents the acceleration of the object.

Area under Velocity-Time Graph

Represents the displacement or distance covered by the object.

First Equation of Motion

The relationship between velocity, acceleration, and time: $v = u + at$.

Second Equation of Motion

The relationship between displacement, initial velocity, acceleration, and time: $s = ut + \frac{1}{2} at^2$.

Third Equation of Motion

The relationship between final velocity, initial velocity, acceleration, and displacement: $v^2 - u^2 = 2as$.

Uniform Circular Motion

Motion of an object traveling at a constant speed in a circular path; it is an accelerated motion because direction changes continuously.

Free Fall

Vertical motion under the influence of gravity alone, where acceleration due to gravity ($g$) is approximately $10\,m/s^2$ or $9.8\,m/s^2$.

Acceleration due to Gravity ($g$)

The acceleration experienced by objects in free fall; taken as negative ($-10\,m/s^2$) when moving upward and positive ($10\,m/s^2$) when falling downward.