Kinematic Class 11 Notes Physics

 Page 1


Motion
Motion
Motion refers to the change in position of an object with respect to time. When an
object changes its position with respect to a reference point, it is said to be in
motion.
Motion can be described in terms of its speed, direction, and acceleration. 
Position, Distance and Displacement:
Position: An object’s position is always expressed in relation to some reference
point, known as the origin. We take into account two physical quantities to express
the change in position.
Distance: This is the actual path that an object travels while in motion. Its
dimensions are [L] and its S.I. unit is 'm '.
Displacement: This term describes the variation between the final and initial
positions of an object during motion.
Differences Between Distance and Displacement: Differences Between Distance and Displacement:
Revision	Notes:	Kinematic
Page 2


Motion
Motion
Motion refers to the change in position of an object with respect to time. When an
object changes its position with respect to a reference point, it is said to be in
motion.
Motion can be described in terms of its speed, direction, and acceleration. 
Position, Distance and Displacement:
Position: An object’s position is always expressed in relation to some reference
point, known as the origin. We take into account two physical quantities to express
the change in position.
Distance: This is the actual path that an object travels while in motion. Its
dimensions are [L] and its S.I. unit is 'm '.
Displacement: This term describes the variation between the final and initial
positions of an object during motion.
Differences Between Distance and Displacement: Differences Between Distance and Displacement:
Revision	Notes:	Kinematic
When an object is moving, the
distance it covers is always positive
and never negative or zero.
An object’s displacement during
motion can be positive, negative or
even zero.
The amount of displacement is
negligible or equal to the distance
covered during motion.
The distance depends on the path
taken by the object.
The magnitude of displacement is
independent of the path travelled
by an object during motion.
It is defined as the total distance
travelled divided by the amount of
time that the motion has occurred.
It describes the division of the time
intervals during which a change in
location or displacement takes place.
It is a scalar quantity.
During motion, it may be positive,
negative or zero.
Distance
Distance Displacement Displacement
It describes the actual path taken
by an object while in motion.
It denotes the difference between
the starting and ending positions.
It is a scalar quantity
It is a vector quantity
The distance travelled is always
more than, or equal to the size of
the displacement
Difference Between Speed and Velocity : Difference Between Speed and Velocity :  
Speed
Speed
 
 
Velocity
Velocity
It is a vector quantity
Throughout motion, it is always
positive.
Page 3


Motion
Motion
Motion refers to the change in position of an object with respect to time. When an
object changes its position with respect to a reference point, it is said to be in
motion.
Motion can be described in terms of its speed, direction, and acceleration. 
Position, Distance and Displacement:
Position: An object’s position is always expressed in relation to some reference
point, known as the origin. We take into account two physical quantities to express
the change in position.
Distance: This is the actual path that an object travels while in motion. Its
dimensions are [L] and its S.I. unit is 'm '.
Displacement: This term describes the variation between the final and initial
positions of an object during motion.
Differences Between Distance and Displacement: Differences Between Distance and Displacement:
Revision	Notes:	Kinematic
When an object is moving, the
distance it covers is always positive
and never negative or zero.
An object’s displacement during
motion can be positive, negative or
even zero.
The amount of displacement is
negligible or equal to the distance
covered during motion.
The distance depends on the path
taken by the object.
The magnitude of displacement is
independent of the path travelled
by an object during motion.
It is defined as the total distance
travelled divided by the amount of
time that the motion has occurred.
It describes the division of the time
intervals during which a change in
location or displacement takes place.
It is a scalar quantity.
During motion, it may be positive,
negative or zero.
Distance
Distance Displacement Displacement
It describes the actual path taken
by an object while in motion.
It denotes the difference between
the starting and ending positions.
It is a scalar quantity
It is a vector quantity
The distance travelled is always
more than, or equal to the size of
the displacement
Difference Between Speed and Velocity : Difference Between Speed and Velocity :  
Speed
Speed
 
 
Velocity
Velocity
It is a vector quantity
Throughout motion, it is always
positive.
It is more than or equal to the
magnitude of the velocity
It is equal to or less than the
speed.
The amount of displacement is equal to the length of the entire path when an
object is moving in a straight line and in the same direction.
In this instance, the average speed and average velocity are of equal magnitude.
This isn’t always the case, though.
Note Note
Scalar and Vector Quantities
Scalar and Vector Quantities
Scalar Quantities Scalar Quantities
Scalar quantities are used to describe physical quantities that only have
magnitude and no direction.
Scalars include things like mass, length, time, distance, speed, work and
temperature, to name a few.
Vector Quantities Vector Quantities
The term “vector quantity” refers to a physical quantity that has both
magnitude and direction.
It includes displacement, velocity, acceleration, force, momentum and
torque.
Scalar Vector
Page 4


Motion
Motion
Motion refers to the change in position of an object with respect to time. When an
object changes its position with respect to a reference point, it is said to be in
motion.
Motion can be described in terms of its speed, direction, and acceleration. 
Position, Distance and Displacement:
Position: An object’s position is always expressed in relation to some reference
point, known as the origin. We take into account two physical quantities to express
the change in position.
Distance: This is the actual path that an object travels while in motion. Its
dimensions are [L] and its S.I. unit is 'm '.
Displacement: This term describes the variation between the final and initial
positions of an object during motion.
Differences Between Distance and Displacement: Differences Between Distance and Displacement:
Revision	Notes:	Kinematic
When an object is moving, the
distance it covers is always positive
and never negative or zero.
An object’s displacement during
motion can be positive, negative or
even zero.
The amount of displacement is
negligible or equal to the distance
covered during motion.
The distance depends on the path
taken by the object.
The magnitude of displacement is
independent of the path travelled
by an object during motion.
It is defined as the total distance
travelled divided by the amount of
time that the motion has occurred.
It describes the division of the time
intervals during which a change in
location or displacement takes place.
It is a scalar quantity.
During motion, it may be positive,
negative or zero.
Distance
Distance Displacement Displacement
It describes the actual path taken
by an object while in motion.
It denotes the difference between
the starting and ending positions.
It is a scalar quantity
It is a vector quantity
The distance travelled is always
more than, or equal to the size of
the displacement
Difference Between Speed and Velocity : Difference Between Speed and Velocity :  
Speed
Speed
 
 
Velocity
Velocity
It is a vector quantity
Throughout motion, it is always
positive.
It is more than or equal to the
magnitude of the velocity
It is equal to or less than the
speed.
The amount of displacement is equal to the length of the entire path when an
object is moving in a straight line and in the same direction.
In this instance, the average speed and average velocity are of equal magnitude.
This isn’t always the case, though.
Note Note
Scalar and Vector Quantities
Scalar and Vector Quantities
Scalar Quantities Scalar Quantities
Scalar quantities are used to describe physical quantities that only have
magnitude and no direction.
Scalars include things like mass, length, time, distance, speed, work and
temperature, to name a few.
Vector Quantities Vector Quantities
The term “vector quantity” refers to a physical quantity that has both
magnitude and direction.
It includes displacement, velocity, acceleration, force, momentum and
torque.
Scalar Vector
Average Velocity and Average Speed:
Average Velocity and Average Speed:
Average Velocity Average Velocity
Average velocity is the total displacement of an object over a certain
period of time, divided by the time interval. In other words, it is the
change in position of an object divided by the time taken for that
change to occur.
Average Velocity = 
      (Final Position - Initial Position) / Time taken
Average Speed Average Speed
Average speed is the distance traveled by an object over a
certain period of time, divided by the time interval. It is the
total distance traveled by an object divided by the time
taken for that journey.
Average Speed = Total Distance Traveled / Time Taken
Page 5


Motion
Motion
Motion refers to the change in position of an object with respect to time. When an
object changes its position with respect to a reference point, it is said to be in
motion.
Motion can be described in terms of its speed, direction, and acceleration. 
Position, Distance and Displacement:
Position: An object’s position is always expressed in relation to some reference
point, known as the origin. We take into account two physical quantities to express
the change in position.
Distance: This is the actual path that an object travels while in motion. Its
dimensions are [L] and its S.I. unit is 'm '.
Displacement: This term describes the variation between the final and initial
positions of an object during motion.
Differences Between Distance and Displacement: Differences Between Distance and Displacement:
Revision	Notes:	Kinematic
When an object is moving, the
distance it covers is always positive
and never negative or zero.
An object’s displacement during
motion can be positive, negative or
even zero.
The amount of displacement is
negligible or equal to the distance
covered during motion.
The distance depends on the path
taken by the object.
The magnitude of displacement is
independent of the path travelled
by an object during motion.
It is defined as the total distance
travelled divided by the amount of
time that the motion has occurred.
It describes the division of the time
intervals during which a change in
location or displacement takes place.
It is a scalar quantity.
During motion, it may be positive,
negative or zero.
Distance
Distance Displacement Displacement
It describes the actual path taken
by an object while in motion.
It denotes the difference between
the starting and ending positions.
It is a scalar quantity
It is a vector quantity
The distance travelled is always
more than, or equal to the size of
the displacement
Difference Between Speed and Velocity : Difference Between Speed and Velocity :  
Speed
Speed
 
 
Velocity
Velocity
It is a vector quantity
Throughout motion, it is always
positive.
It is more than or equal to the
magnitude of the velocity
It is equal to or less than the
speed.
The amount of displacement is equal to the length of the entire path when an
object is moving in a straight line and in the same direction.
In this instance, the average speed and average velocity are of equal magnitude.
This isn’t always the case, though.
Note Note
Scalar and Vector Quantities
Scalar and Vector Quantities
Scalar Quantities Scalar Quantities
Scalar quantities are used to describe physical quantities that only have
magnitude and no direction.
Scalars include things like mass, length, time, distance, speed, work and
temperature, to name a few.
Vector Quantities Vector Quantities
The term “vector quantity” refers to a physical quantity that has both
magnitude and direction.
It includes displacement, velocity, acceleration, force, momentum and
torque.
Scalar Vector
Average Velocity and Average Speed:
Average Velocity and Average Speed:
Average Velocity Average Velocity
Average velocity is the total displacement of an object over a certain
period of time, divided by the time interval. In other words, it is the
change in position of an object divided by the time taken for that
change to occur.
Average Velocity = 
      (Final Position - Initial Position) / Time taken
Average Speed Average Speed
Average speed is the distance traveled by an object over a
certain period of time, divided by the time interval. It is the
total distance traveled by an object divided by the time
taken for that journey.
Average Speed = Total Distance Traveled / Time Taken
 
 
Instantaneous Velocity and Instantaneous Speed
Instantaneous Velocity and Instantaneous Speed
Instantaneous velocity Instantaneous velocity
Instantaneous velocity is the velocity of an object at a specific instant
in time. 
It is the rate of change of an object's position with respect to time at
that specific moment.
Instantaneous Velocity = lim ( ?t ? 0) ?x / ?t
Its dimensions are [M LT ] and its S.I. unit is m/s.
0
-1
Instantaneous Speed Instantaneous Speed
Instantaneous speed is the speed of an object at a specific instant in
time. It is the magnitude of the instantaneous velocity of the object
Instantaneous Speed = |Instantaneous Velocity|
Its dimensions are [M L T ] and its S.I. unit is m/s.
0 -1
Acceleration
Acceleration is the rate of change of an object's velocity with respect to time. It
is the rate at which an object's velocity is changing in magnitude or direction,
or both.
For example, if a car is initially traveling at a velocity of 30 km/h to the east
and after 5 seconds it is traveling at a velocity of 60 km/h to the east, its
acceleration can be calculated as:
      Acceleration = (60 km/h - 30 km/h) / 5 s = 6 km/h/s to the east
This means that the car's velocity is increasing at a rate of 6 kilometers per
hour every second to the east.
a=vdv
dx