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Newtons 1st Law:

An object at rest tends to stay at rest, and an object in motion tends

to stay in uniform motion, with a constant speed in the samedirection unless acted upon by an external unbalanced force.

This law was derived from Galileo's Principle of Inertia which states: "A

body moving on a level surface will continue in the same direction at

constant speed unless disturbed."

Newtons 2nd Law:

'An applied force is directly proportional to the rate of change of

momentum'.

In other terms:

F P

t

Newtons 3rd Law:

All forces occur in pairs, and these two forces are equal in

magnitude and opposite in direction.OR

If body A exerts a force F on body B then body B exerts an equal

and opposite force F on body A.

In other terms:

"For every action, there is an equal and opposite reaction."

EXAMPLE:

When you sit in your chair, your body exerts a downward force on

the chair and the chair exerts an upward force on your body. There

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are two forces resulting from this interaction - a force on the chair

and a force on your body. These two forces are called action and

reaction forces and are the subject of Newton's third law of

motion.

Aristotles Ideas and his laws of motion

Aristotle's Laws of Motion

Aristotle's Laws of Motion were based on his belief that rest was thenatural state of a body. That is, something moves only if acted upon

by a force. Aristotle also thought a heavy body should fall faster than alight one. He did not subject these ideas to *experiment. Not until

Galileo Galilee did anyone bother to check whether bodies of differentweight actually did fall at different speeds.

Aristotles Laws State:

A body, not acted on by any force, remains at absolute rest.

Nothing moves unless you push it. [it is moved by a mover]

The most Natural state is Rest.

Force is proportional to the velocity. F=mv

Heavy objects fall faster than light objects.

There is no such thing as a vacuum.

We will eventually see thatphysical experimentshows that all of

these statements are actuallyFALSE.

If I have seen farther than other men, it is because I have stood on the shouldersof giants." -Isaac Newton

When Newton made that famous statement, he was referring to such giants asTycho Brahe, Johannes Kepler, and, most specifically, Galileo Galilee.

http://www.321books.co.uk/biography/galileo-galilei.htmhttp://www.321books.co.uk/biography/galileo-galilei.htm

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It was Galileos concept of inertia which lead Newton to discover

his first law. In opposition to Aristotles laws Galileo boldly stated

and proved that these laws were false. He reasoned that moving

objects eventually stopped moving due to a force called friction.

He also proved that heavy and light objects fall at the same speed.