Motion:
Movement of any object from one position to another position with respect to the observer is called as
Motion.
Motion Along a Straight Line:
When an object moves along a straight line, the motion of the object is called rectilinear motion. For
example; motion of a car on highway.
Vectors and Scalar Quantities:
• Vector is a quantity which has both magnitude and direction. For example, Force, position, etc.
• Scalar is a quantity with which direction is not associated. For example, Mass, temperature, time, etc.
Distance:
• Length of path covered by a moving an object in the given time irrespective of the direction
is called distance. It is a scalar quantity.
• Its SI unit is metre(m).
Displacement:
• The shortest distance measured from initial to the final position of an object is known as the displacement.
• It is a vector quantity.
Uniform Motion:
• When an object covers equal distances in equal intervals of time, it is said to be in uniform motion.
Non-Uniform Motion:
• When an object covers unequal distances in equal intervals of time, it is said to be in non-uniform motion.
Speed (s):
• The distance travelled by an object in unit time is referred to as speed.
• Its SI unit is metre/ second (m/s).
• It is a scalar quantity.
• Average speed: For non-uniform motion, the average speed of an object is obtained by dividing the total
distance travelled by an object by the total time taken.
Velocity (v):
• Speed of an object in a particular direction is named as velocity, i.e., it is the displacement of body in unit
time.
• Acceleration (a):
• The rate of change of velocity is termed as acceleration.
• It is represented as:
, • Its SI unit is metre/seccond2 (m/s2).
• It is a vector quantity.
• The acceleration is taken to be positive if it is in the direction of velocity and negative when it is opposite to
the direction of velocity.
• Negative acceleration is also named as retardation or deacceleration.
• An object moving on a circular path though with uniform speed, is always said to be accelerated as it
changes its direction every moment.
• Uniform acceleration: When velocity of body changes by equal amounts in equal time intervals,
acceleration is said to be uniform. For example: Motion of a freely falling ball.
• Non - uniform acceleration: When velocity of body changes by unequal amounts in equal intervals if time,
acceleration is said to be non - uniform. For example: Motion of car.
Graphical Representation of Motion
1. Distance -Time Graph for Uniform Speed:
Distance -Time graph for uniform speed, is a straight line as shown below:
2. Distance -Time Graph for Non-Uniform Speed:
Distance -Time graph for uniform speed, is obtained in the form of a curve as shown below:
3. Distance -Time Graph for a Body at Rest:
Distance -Time graph for a body at rest is a straight line parallel to the time axis (x-axis):
Movement of any object from one position to another position with respect to the observer is called as
Motion.
Motion Along a Straight Line:
When an object moves along a straight line, the motion of the object is called rectilinear motion. For
example; motion of a car on highway.
Vectors and Scalar Quantities:
• Vector is a quantity which has both magnitude and direction. For example, Force, position, etc.
• Scalar is a quantity with which direction is not associated. For example, Mass, temperature, time, etc.
Distance:
• Length of path covered by a moving an object in the given time irrespective of the direction
is called distance. It is a scalar quantity.
• Its SI unit is metre(m).
Displacement:
• The shortest distance measured from initial to the final position of an object is known as the displacement.
• It is a vector quantity.
Uniform Motion:
• When an object covers equal distances in equal intervals of time, it is said to be in uniform motion.
Non-Uniform Motion:
• When an object covers unequal distances in equal intervals of time, it is said to be in non-uniform motion.
Speed (s):
• The distance travelled by an object in unit time is referred to as speed.
• Its SI unit is metre/ second (m/s).
• It is a scalar quantity.
• Average speed: For non-uniform motion, the average speed of an object is obtained by dividing the total
distance travelled by an object by the total time taken.
Velocity (v):
• Speed of an object in a particular direction is named as velocity, i.e., it is the displacement of body in unit
time.
• Acceleration (a):
• The rate of change of velocity is termed as acceleration.
• It is represented as:
, • Its SI unit is metre/seccond2 (m/s2).
• It is a vector quantity.
• The acceleration is taken to be positive if it is in the direction of velocity and negative when it is opposite to
the direction of velocity.
• Negative acceleration is also named as retardation or deacceleration.
• An object moving on a circular path though with uniform speed, is always said to be accelerated as it
changes its direction every moment.
• Uniform acceleration: When velocity of body changes by equal amounts in equal time intervals,
acceleration is said to be uniform. For example: Motion of a freely falling ball.
• Non - uniform acceleration: When velocity of body changes by unequal amounts in equal intervals if time,
acceleration is said to be non - uniform. For example: Motion of car.
Graphical Representation of Motion
1. Distance -Time Graph for Uniform Speed:
Distance -Time graph for uniform speed, is a straight line as shown below:
2. Distance -Time Graph for Non-Uniform Speed:
Distance -Time graph for uniform speed, is obtained in the form of a curve as shown below:
3. Distance -Time Graph for a Body at Rest:
Distance -Time graph for a body at rest is a straight line parallel to the time axis (x-axis):
