1. CAPACITY BUILDING PROGRAMME
FOR PHYSICS TEACHERS
SENIOR SECONDARY LEVEL
TOPIC : - DRAWING AND READING SKILLS OF
GRAPHS IN KINEMATICS
Presented By – RAJEEV KUMAR SHARMA( PGT)
GAIL DAV PUBLIC SCHOOL,DIBIYAPUR
2. CONTENT:-
1.WHAT IS GRAPH ?
2.DISPLACEMENT TIME GRAPHS FOR DIFFERENT SITUATIONS.
3.VELOCITY TIME GRAPHS FOR DIFFERENT SITUATIONS
4.SPECIAL CASES FOR DRAWING AND READING GRAPHS.
5.GRAPH CONVERSION.
3. WHAT IS A GRAPH ?
• A GRAPH IS A STRAIGHT OR CURVED LINE WHICH SHOWS VARIATION OF ONE
PHYSICAL QUANTITY W.R.T OTHER, WHICH ARE INTER-RELATED.
• IN THE RELATION OF TWO PHYSICAL QUANTITIES, THE QUANTITY WHICH WE
CHANGE AT OUR WILL IS CALLED IDEPENDENT VARIABLE AND THE QUANTITY
WHCH VARIES AS A RESULT OF THIS CHANGE IS CALLED DEPENDENT VARIABLE.
• FOR EXAMPLE :
IN F = ma , F ∝ 𝑎
AND
IN S= u t + 1/2 at2 , S ∝ 𝑡2 ETC.
4. THERE ARE TWO TYPES OF QUESTIONS
BASED ON GRAPHS IN KINEMATICS
• QUESTIONS BASED ON PLOTTING THE GRAPHS
•QUESTIONS BASED ON READING THE GRAPHS
6. (II) WHEN THE OBJECT IS IN UNFORM MOTION ALONG A STRAIGHT
LINE (OR OBJECT MOVES WITH CONSTANT VELOCITY )
7. (III) WHEN THE OBJECT IS MOVING WITH CONSTANT NEGATIVE VELOCITY
8. (IV) WHEN THE OBJECT IS MOVING WITH INCREASING VELOCITY.
9.
10. READING THE GRAPHS( READING SKILL ) :
* WHAT WE CONCLUDE FROM THE GIVEN X-T GRAPHS?
( a ) X – T , GRAPH : - 1
CONCLUSION :
Here the object is initially at rest
and away from origin and starts
running fast towards the origin as
time increases.
Velocity = slope of x-t graph
= tan θ ( negative and
increasing)
So, v- negative & increasing
a - negative
11. (b) X – T , GRAPH :- 2
CONCLUSION :
Here the object is moving with
some initial velocity and its
velocity decreases with time as it
moves towards the origin.
Velocity = slope of x-t graph
= tan θ ( negative and
decreasing)
So, v - negative & decreasing
a - positive
12. (c) X – T , GRAPH - 3
CONCLUSION:
Here the object is moving with
some initial velocity and its
velocity decreases with time as
it goes away from origin.
Velocity = slope of x-t graph
= tan θ ( positive
and decreasing)
So, v - positive & decreasing
a - negative
13. VELOCITY-TIME GRAPH OF AN OBJECT
(i) WHEN THE OBJECT MOVES WITH CONSTANT VELOCITY:-
AREA UNDER V-T GRAPH GIVES
DISPLACEMENT.
AREA UNDER V-T GRAPH B/W t1 & t2
=AREA ABCD
=CDXAC
=(t2-t1) x v
=DISPLACEMENT
14. • (II ) WHEN THE OBJECT MOVES WITH CONSTANT ACCELERATION:-
• SLOPE OF V-T GRAPH
GIVES ACCELERATION
• AREA UNDER V-T GRAPH
= DISPLACEMENT
15. * Displacement – Time Graph of a
ball projected vertically upward :
( a ) When the displacement of
ball is taken from ground and
vertically upward direction as
positive.
( b) When the displacement of
ball is taken from person and
vertically upward direction as
positive.
16. +
• Distance – Time Graph of a
ball pojected vertically
upward :
• Here initial point is taken at
ground.
17. * Velocity – Time Graph of
a ball pojected vertically
upward :
* From v = u - g t ,
we calculate velocity of ball.
* Speed – Time Graph of
a ball pojected vertically
upward :
18. Velocity – Time Graph of
a freely falling ball :
• Here we take height of ball
from ground( ie origin at
ground ) and vertically upward
direction as positive.
• From v = u + g t , we calculate
velocity of ball.
19. FOR DISPLACEMENT :
Here Origin is at Ground.
WHEN t = 0 S, x = 20m
WHEN t = 1 S, x = 15m ( Ball Travels 5 m from
man)
WHEN t = 2 S, x = 0 m ( S= ut+1/2 at2 )
WHEN t = 3 S, x = 15 m
WHEN t = 4 S, x = 20 m
FOR DISTANCE :
Here Initial point is man
WHEN t = 0 S, d = 0m
WHEN t = 1 S, d = 5m ( Ball Travels 5 m from
man)
WHEN t = 2 S, d = 20 m
WHEN t = 3 S, = 20 +15 = 35 m
WHEN t = 4 S, d = 20 + 20 = 40 m
