KINEMATICS

"Kinematics is the branch of Physics in which we discuss bodies at rest or motion
without the reference of external agent that causes motion or rest."
OR
"The branch of physics which deals with the description of motion of objects without
reference to the force or agent causing motion in it, is called Kinematics."

REST: -

"If a body does not change its position with respect to its surroundings then
the body is said to be in a state of rest."

MOTION: -

"If a body continuously changes its position with respect to its surrounding
than it is said to be in a state of motion."

TYPES OF MOTION: -

Motion of objects can be divided into three categories.

(i) TRANSLATIONAL MOTION (ii) ROTATIONAL MOTION (iii) VIBRATIONAL MOTION

TRANSLATIONAL MOTION: -

"Motion of a body in which every particle of the body is being displaced by the same amount is called Translational Motion".

EXAMPLE: (i) Motion of a person on a road. (ii) Motion of a car or truck on a road.

ROTATIONAL MOTION: -

"Distance between two points in a particular direction is called Displacement." OR Displacement may also be defined as "the minimum distance between two points in a particular direction."

It is a vector quantity and is always directed from the initial point to the terminal point. It is denoted by "d".

SPEED: -

"Distance covered by a moving body in one second is called its Speed". OR "Distance covered by a body in unit time is called Speed".

Speed is a scalar quantity.

FORMULA: -

Speed = Distance traveled/Time taken
OR
v = S/t

UNIT: -

Unit of speed in S.I system is "m/sec".

AVERAGE SPPED: -

                                    “Total distance covered in total time is called average speed”

FORMULA: -

                                                            Average speed = Total displacement / Total time

                                                                                                OR

                                                                                    <V> = S / t

UNIFORM SPEED: -

                                    “Same distance covered in same time is called uniform speed’

VARIABLE SPEED: -

                                    “Different distances covered in different time is called variable speed”

INSTANTANEOUS SPEED: -

                                    “Distances covered at any instant of time is called instantaneous speed”

FORMULA: -

                                                            V _ins = limit ΔS / Δ t

                                                                        ^Δt→0

VELOCITY: -

"Distance covered by a body in a particular direction in one second is called Velocity".
OR
"Displacement of a body in unit time is called Velocity".
OR
"Change of position of a body per second in a particular direction is called Velocity."

FORMULA: -

Velocity = displacement/time

v = ΔS / t

UNIT: -

In S.I system unit of velocity is meter/second.
It is a vector quantity.

AVERAGE VELOCITY: -

                                    “Total displacement covered in total time is called average speed”

FORMULA: -

                                                            Average velocity = Total displacement / Total time

                                                                                                OR

                                                                        < V > = S / t

UNIFORM VELOCITY: -

                                    “Same displacement covered in same time is called uniform speed’

VARIABLE SPEED: -

                                    “Different displacements covered in different time is called variable speed”

INSTANTANEOUS SPEED: -

                                    “Displacements covered at any instant of time is called instantaneous speed”

FORMULA: -

                                                            V_ins = limit ΔS / Δ t

                                                                        ^Δt→0

ACCELERATION: -

"The rate of change of velocity of a body is called Acceleration." OR "Change in velocity of a body in unit time is called its acceleration."

It is denoted by "a". It is a vector quantity. If a body moves with uniform velocity or constant velocity then its acceleration will be zero. UNIT:  - In S.I system the unit of acceleration is m/sec2.

FORMULA: -

Acceleration = change in velocity/time
OR
a = ΔV/t

AVERAGE ACCELERATION: -

                                    “Total change in velocities in total time is called average speed”

FORMULA: -

                                                            Average acceleration = Total change invelocities / Total time

                                                                                                OR

                                                                        < a > = ΔV / t

UNIFORM ACCELERATION: -

                                    “Same change of velocities in same time is called uniform speed’

VARIABLE ACCELERATION: -

                                    “Different change of velocities in different time is called variable speed”

INSTANTANEOUS ACCELERATION: -

                                    “The change of velocities at any instant of time is called instantaneous speed”

FORMULA: -

                                                            a _ins = limit ΔV / Δ t

                                                                        ^Δt→0