Time motion with velocity distance travel.pptx

Time motion

1. 167

MOTION

Life is a full circle, widening until it joins the circle
motions of the infinite

o

2. Motic

Co

What 15 Motion

ancept :-

3. E)

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4. DISTANCE

Distance moved :- It is the actual length of the path travelled by a body.

Starting & Ending
point

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5. DISPLACEMENT

Displacement + It is the length of the shortest path travelled by a body

from its initial position to its final position.

Starting & ending
point

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6. SPEED

Speed :- Speed of a body is the distance travelled by the body in unit
time.

Speed = Distance
Time

If a body travels a distance s in time t then its speed v is

ei.)
y

The SI unit of speed is metre per second m/s or ms a

Since speed has only magnitude it is a scalar quantity,
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7. VELOCITY

The rate of motion of a body is more meaningful if we specify its direction of
motion along with speed. The quantity which specifies both the direction of

motion and speed is velocity

Velocity Velocity of a body is the displacement of the body per unit time

Velocity = Displacement
Time taken

Since velocity has both magnitude and direction, it is a vector quantity

8. [67

©

ACCELERATION

The quantity which specifies changes in velocity is acceleration,
Acceleration :- It is the change in velocity of a body per unit time. ( or
the rate of change of velocity.)
Acceleration = Change in velocity
Time

‚If the velocity of a body changes from initial value u to final value y in
time t, then acceleration à is

; na a ,
t «The SI unit of acceleration is ms "?

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e

9. PLOTTING POINTS

We already know how to plot points on a graph. So let's recall them, Suppase |

want to plot points (3, 4) on a graph, it w | be as follow

Po lo 4) 5 In tt m way, we can plot mar
4 o
x ) Y } 1 2Tapn
\ | 2
a
1
x
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10. GRAPHS AND ITS
TRES

11. DISTANCE TIME

= GRAPH

The change in the position of a body with time can be represented on
the distance time coh In this graph istance is taken on the Y-axis
and time is taken on the X - axis. The distance time graph for uniform
speed is a straight line (linear ).

This is because in uniform speed a body travels equal distances in equal
intervals of time. We can determine the speed of the body from the
distance - time graph.

They are used to find speed or velocity of body.

The slope of it gives speed of body.

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12. There are 3- “Tps | of distance time
wignaphs. : lle!

13. 3. When a body is moving with Non uniform speed — The body covers unequal
distances in equal intervals of time,

|
| increasing

/
| / decreasing

Ê / speed freed

tc

t—

‘These curves are called parabola,

So, greater the angle, greater is the slope and greater is the speed

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14. DISPLACEMENT TIME
GRAPH

it's sloy

15. 2. Body moving with uniform speed -

A
| p Where Q1>Q2
8 Velocity of A > Velocity of B

@
t—
3. Body moving with variable/non uniform velocity -

velocity velocity
decreases

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16. VELOCITY TIME
GRAPH

17. ®
CASE -1

If the body is moving with constant speed.

IL
y

Slope = 0
Acceleration = ms *?

t—

Constant speed — If the body moves with constant velocity/speed then graph is straight
line parallel to time axis and slpoe and acceleration will be 0.

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18. CASE - IT
When a body is moving with uniformly changing speed -

a.) If speed increases uniformly

This slope is known as positive slope and slope gives
uniform acceleration,
=
b) If speed is decreasing uniformly -

+

raph is straight line slope downwards. Hence, the slope is

negative, The slope of this graph gives retardation.

Area in both cases (a & b) gives distance travelled by body,

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19. CASE - III
Non uniformly changing speed.

a.) If speed increases non uniformly,

The graph is a curve moving upward. The slope of tangent

drawn at any point on curve is positive and is equal to
acceleration of body,
==.
b,) If speed decreases non uniformly.
u The graph is a curve moving downwards and the slope of
tangent is negative and gives the value of retardation.
aE

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20. ACCELERATION TIME
_ GRAPH

CASE - Il

21. EQUATIONS OF MOTION BY
GRAPHICAL METHOD

The motion of a body moving with uniform acceleration can be described
with the help of three equations called equations of motion.

The equations of motion are ;- Where u - is the initial velocity
i)v=u+a vis the final velocity
ii) s=ut+ Aal a - is acceleration

ii) 2as = =p? t= is the time

8 - is the distance traveled

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22. Y

CIRCULAR

l norm € ircular Motion := If a body moves in a circular path with uniform

speed, its motion is called uniform circular motion
Uniform circular motion is accelerated motion because in a circular motion a body

continuously changes its direction,

The circumference of a circle of radius r is given by 2zr, If a body takes time t to go once

around the circular path, then the velocity v is given by

y

23. Thanks for watchi

Name - Mridul Ver
Class -9-A
Roll No. - 10

OMridul -.