CHAPTER 12: GRAVITATION AND NEWTON'S SYNTHESIS

Newton's Law of Universal Gravitation

Vector Form of Newton's Law of Universal Gravitation

Gravity Near the Earth's Surface; Geophysical Application

Satellites and "Weightlesness"

Kepler's Laws and Newton's Sythesis

Gravitational Field

Types of Forces in Nature

Principle of Equivalence; Curvature of Space; Black Holes

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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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In Vector Form: image

The gravitational forces acting between the two particles form action-reaction pair. Where r^12 is a unit vector pointing from m2 to m1. image

Acceleration due to gravity varies on the Earth's surface because of the altitude, shape of the Earth and the local geology.

For example: image

Gravitational constant cn be related to local acceleration of gravity.
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From the formula: image

Satellites

Weightlesness

Kepler's Law (Laws of Planetary Motions)

Newton's synthesis

is the gravitationalForce per unit mass: image

Gravitational Field due to a single mass, M: image

Gravity

Electromagnetism

Weak Nuclear Forces

Strong Nuclear Forces

binds proton and neutrons together in the nucleus of an atom.

responsible for some types of radioactive decay

occurs between electrically charged particles.

an invisible force that pulls objects toward each other.

1st Law: The law of ellipses

2nd Law: Law of equal Areas

3rd Law: Law of Periods

Each planet moves in an elliptical way with its star(Sun) at one focus.

an imaginary line drawn from each planet to the Sun sweeps out equal areas n equal times.

The square of planet's orbital time is proportional to its average distance from the star (Sun) cubed.

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an object in space that orbits or circles around a bigger object.

natural (such as the moon orbiting the Earth)

artificial (such as the International Space Station orbiting the Earth).

The tangential speed must be high enough so that the satellites does not return to Earth but not so high that it escapes Earth's gravity altogether.

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Objects in orbit are said to experience weightlessness.

still have gravitational force on them.

the satellite is in free fall, there is no normal force.

also known as Apparent Weightlesness (can be experienced on Earth but brief)

Examples: Man paragliding, astronauts on the Moon, free falling elevator.

fundamental law of physics that states that gravitational and inertial forces are of a similar nature and often indistinguishable.

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