1D Kinematics notes

copygrouperMechanics

Nov 13, 2013 (3 years and 11 months ago)

106 views


1D Kinematics


Distance Time (DT) Graph

Slope of a DT graph gives speed


D


This is a graph of an object

not
moving.


No

slope = No speed

T


Distance Time (DT) Graph


Slope of a DT graph gives speed


D


This is a graph of an object

moving with constant speed.


Straight line has one slope =
one speed or constant speed


T


Distance Time (DT) Graph


Slope of a DT graph gives speed


D


This is a graph of an object

moving with changing speed.


Increasing

slope = increasing
speed = accelerating


T


Distance Time (DT) Graph


Slope of a DT graph gives speed


D


This is a graph of an object

moving with changing speed.


Decreasing slope = decreasing
speed = Slowing down


T


Velocity Time (VT) Graph

Slope of a VT graph gives Acceleration


V


This is a graph of an object

moving with constant velocity.


No

slope = No acceleration

T


Velocity Time (VT) Graph


Slope of a VT graph gives Acceleration


V


This is a graph of an object

moving with constant
acceleration.

Straight line has one slope =
one or constant acceleration


T


Velocity Time (VT) Graph


Slope of a VT graph gives Acceleration


V


This is a graph of an object

moving with changing slope.


Increasing

slope = increasing
speed=non
-
uniform acceleration


T


Velocity Time (VT) Graph


Slope of a VT graph gives acceleration


V


This is a graph of an object

moving with Non uniform
acceleration.


Decreasing slope = decreasing
acceleration


T


Velocity Time (VT) Graph


Area under a VT graph gives displacement

V


Here the area under the graph
is a triangle

Area = ½ Base x Height


T


Velocity Time (VT) Graph


Area under a VT graph gives displacement

V


Here the area under the graph
is a triangle and a rectangle

Area = [½ Base x Height] +


[Length x Width]


T

Actual distance covered is called distance



The distance from the origin is called
displacement

Difference between Distance and
Displacement


Distance is always
positive
, but
Displacement can be either
positive or
negative

Distance
is a scalar

Displacement
is a vector

Difference between Distance and
Displacement

Speed is only magnitude


Velocity gives you a magnitude and a direction

Difference between Speed and
Velocity


Speed is always
positive

Velocity can be either
positive or negative

Speed
is a scalar

Velocity
is a vector

Difference between Speed and
Velocity


Speed = Distance/time ( V=∆d/ ∆ t)

Unit of speed in metric system is m/s



Constant Speed or Velocity

1

Slope of a VT graph gives acceleration

a = ∆V/∆t

Or a = V
f



V
i

/t

Or


Acceleration

V
f

= V
i

+ at

3

a = g = 9.8m/s
2

or 10m/s
2

That means an object will increase speed at the rate
10m/s every second

Since Gravity acts in the downward direction,
objects speed up when dropped and slow down
when thrown up.

Acceleration due to Gravity

a)
Information not given, don’t know

b)
Zero

c)
10m/s

d)
-
10m/s

When a ball is thrown up, what is the
velocity at the tippity top?

a)
Information not given, don’t know

b)
Zero

c)
10m/s
2

d)
-
10m/s
2

When a ball is thrown up, what is the
acceleration at the tippity top?

Using
V
f

= V
i

+ at

And

Av. Velocity=
(V
f

+V
i

)/2

And

V=d/t

We get





4
th

Equation

V
f
2

= V
i
2

+ 2ad


4

Using
V
f

= V
i

+ at

And

Av. Velocity=
(V
f

+V
i

)/2

And

V=d/t

We also get





5
th

Equation

d=V
i
t+(
½
)at
2


5