Transcript 5.There are no gravitational forces in space

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ATIKA ULYA AKMAL / 16019/2010
WELCOME
ELMA RAFIKATO / 18049 / 2010
OUR
PRESENTATION
INTRODUCTION
THEORITICAL
MISSCONCEPTION
ELABORATION
CLOSING
The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
1.Physics is basic science that has relation with the nature
fenomenas. Some field of physics such as motion,
fluids, colour, heat, electricity, light and magnetism,
and topics at modern physics like relativity, structure of
atoms, solid substance, nuclear physics, particle of
elementary, cosmology and astrophysics.
2.Physics was developed from observations and
experiments. Experiments were carried out using the
scientific method.
3. In understanding the concepts of physics that scientists
have been developed, there is the possibility of
differences in understanding of physics concepts.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
4. There are many causes of misconceptions in
understanding the concepts, principles and laws
of physics.
5. To understand the physics concepts developed
to fit the scientists, it must be analyzed carefully,
looking for more references
6. Gravity was developed by Isaac Newton's famous
law of universal gravitation with. However, in the
application of the concept of gravity in daily life,
there are misconception
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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Newton's law of universal
gravitation states that
every point mass in the
universe attracts every
other point mass with a
force that is directly
proportional to the product
of their masses and
inversely proportional to
the square of the distance
between them.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The value of "g" (9.82 m/s2) is the
average measure of the strength of
Earth's gravitational field (i.e., the
acceleration produced on a mass
regardless of the composition of the
mass.) The value of "g" can vary locally
depending on subsurface mass (e.g.,
plutonic bodies) and so the value (9.82
m/s2) is an average.
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Missconception About Gravitation
1.The moon is not falling
2. The moon is not in free fall
3.The force that acts on apple is not the same as the force
that acts on the moon.
4. The gravitational force is the same on all falling bodies.
5. There are no gravitational forces in space.
6. The gravitational force acting on the Space Shuttle is
nearly zero.
7. The gravitational force acts on one mass at the time.
8. Moon stays in orbit because the gravitational force on it
is balanced by the centrifugal force acting on it.
9. Weighlessness means there is not gravity.
10. The Earth’s spinning motion causes gravity.
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The moon is not falling.
Moon is fall
because it move with
a velocity which acted
centripetal
acceleration (as) down
to center of moon
orbit (earth). We can
see on the figure
below.
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Figure E-1. The
gravitational force one
object exerts on a
second object is directed
toward the first object,
and is equal and
opposite to the force
exerted by the second
object on the first
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
 F  mbl as
Where
M b mbl
mbl a s  G
rb2
v2
M
 G 2b
rb
rb
v
G
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Mb
rb
So that
M b mbl
 F  Fg  G r 2
b
v2  G
Mb
rb
G = 6,67 x 10-11 Nm2/kg2
Mb = 5,98 x 1024 kg
rb = 4,23 x 107 m
so that the magnitude of moon
velocity is 3,07 x 103 m/s. This value
is the minimum velocity that needed
by moon to move arround its orbit.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
From that equation above we can
get two conclusion, those are:
If the velocity is more larger than
minimum velocity value, so that the
moon will be flung away to outside
orbit.
If the velocity is more smaller than
minimum velocity value, so that the
moon will be attracted to the earth.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
The moon is free fall
The condition an object experience the falling
bodies is the its magnitude of acceleration is
the same with acceleration of gravity in the
earth surface. But, this motion only be act on
the object that near from earth surface.
Because the distance between moon and
earth very near (long range order = 107) so
that the magnitude of acceleration that be
acted by moon very small (milliar order).
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
For calculate the magnitude of gravity which
be acted by moon can be done with:
M bm
M bm
… (5)
g G 2 G
2
r


R

h
b
Where, b
h = the distence of object from the earth
surface
Rb = the radius of earth
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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Apogee and Perigee is called Free
fall
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The force that acts on apple is the same as
the force that acts on the moon.
The force is gravity. But, the magnitude of force
that acts on the apple is not same as the
magnitude of force that acts on the moon,
because its magnitude depends of the distance
between two objects or earth surface. If an object
be on near from earth surface so it will be felt
the small gravity and the other way.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
The relationship between the
force of gravity (Fgrav)
between the earth and any
other object and the distance
that separates their centers
(d) can be expressed by the
following relationship
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
The gravitational force is not same on
all falling bodies
The gravitational force that be felt by
the falling bodies depends of its
mass. This statement is true because
the gravitational force is the
interaction force between two or
more mass
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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Be in mutual accord with this equation:
then
… (6)
m1m2
Fg  G 2
r12
m1
g G 2
r
Where, r = the distance of two objects
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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As learned in an earlier unit,
free fall is a special type of
motion in which the only
force acting upon an object
is gravity. Objects that are
said to be undergoing free
fall, are not encountering a
significant force of air
resistance; they are falling
under the sole influence of
gravity. Under such
conditions, all objects will
fall with the same rate of
acceleration, regardless of
their mass
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
There are gravitational force in space.
But, the magnitude of gravitational force
are small because the distance between an
objects in the space very far.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The space shuttle orbits
Earth at an altitude of only a
few hundred miles and Earth
has a radius of a few
thousand miles, so shuttle
astronauts are only a little
farther from Earth's center
than their friends back
home. Astronauts are
weightless because they are
in freefall not because there
is no gravity in space.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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Newton's law of gravity says
there is a gravitational force
between any two objects in
the universe and this force
weakens with distance but
extends infinite distances.
Astronauts orbiting the Earth
in the space shuttle are
weightless, so people might
think that there is no gravity in
space. However this can not
be true because Earth's gravity
is what keeps the shuttle
orbiting Earth.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
The gravitational force on the Space
Shuttle is not nearly zero.
Although, the value is small but it
is still can be calculated by the
equation:
m
m
g G
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r
1
2
G
1
R  h 2
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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There is still a weak gravitational force in very
deep space because the gravitational force
gets smaller as the distance increases, but it
never reaches zero. Hence in very deep space
gravitational forces are very weak, but they
are still there.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The gravitational force is not acts just on one mass,
but the gravitational force acts between two or more
mass.
While an object still be on the earth surface
so it is still feel the gravity from earth. For
example, on the falling object. The object
can be gone down causes gravity that act
from earth surface.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
Moon stays in orbit not caused by the centrifugal force, but moon
stays in orbit because an velocity that be produced sentripetal
acceleration that act go in the direction to the center orbit.
This explanation about that can we found on the satelite
motion. If a satellite stopped moving, it would fall
directly to Earth. But at the very high speed a satellite
has, it would quickly fly out into space (Fig. E-2) if it
were not for the gravitational force of the Earth pulling it
into orbit. In fact, a satellite is falling (acceleration
toward Earth), but its high tangensial speed keeps it from
hitting Earth.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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Figure E-2. A
moving satellite
“falls” out of a
straight-line path
toward the Earth
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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No matter where an object be there so it will
feel the gravitational force. That caused an
object weighlessness is its mass.
We know that from this equation:
where g is not zero (g ≠ 0).
W  Fg  mg
We can get two concluation, those are:
If the mass is zero (m = 0), so the gravitational
forse is zero too.
If the mass is not zero (m ≠ 0), so the
gravitational force is not zero too.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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Between the Earth and the
Moon there is a point called
the Lagrange point: it's the
distance from both the Earth
and the Moon that their pulls
are equal. At this point you
would 'float' forever, at least
until another body comes
near and adds it's gravity to
the mix.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
The gravitational force can be caused by
interaction between two mass. The that
interaction can be caused and make the
gravity.
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are:
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The magnitude of moon velocity can be found by Second Newton’s Laws. There are: