Inertia

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Inertia
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Definition of Inertia Inertia is the natural
tendency of an object to remain in its current
state of motion. The amount of an objects
inertia is directly related to its mass.
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What makes an object move, or stay at rest?
(a) Aristotles (384-322 B.C.E.) observations led
him to believe that an object would remain at a
constant speed if a constant force was exerted on
it. (b) Jean Buriden (1300-1358) believed objects
stayed in motion because they possessed impetus
- something inside that maked them continue to
move.
Who do you believe?
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What makes an object move, or stay at rest?
Galileo (1564-1642) carefully considered both
ideas. He conducted a three part thought in an
attempt to understand why objects move the way
they do.
Although friction stops these results from
occurring in nature, Galileo correctly surmized
the nature of motion from his thought experiments.
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What makes an object move, or stay at rest?
(a) Aristotles (384-322 B.C.E.) observations led
him to believe that an object would remain at a
constant speed if a constant force was exerted on
it. (b) Jean Buriden (1300-1358) believed objects
stayed in motion because the possessed impetus
- something inside that maked them continue to
move. (c ) Galileo (1564-1642) surmized an
objects motion remains unchanged, because there
is no force resisting the motion.
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Galileo had identified the natural tendency of
mass to continue doing what it is already doing -
that is, to continue in uniform motion or remain
at rest. Galileo was defining inertia.
Interestingly, inertia is the only classical
physics law that is incorporated into Einsteins
theories of the nature of our universe.
Inertia introduces the concept of force - a push
or pull on an object that causes change in
motion. Kinematics - the study of motion Dynamics
- the study of why things move, which involves
forces.
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Applying Galileos idea of inertia
(a) A marble is fired into a circular tube that
is anchored onto a frictionless table top. Which
path will the marble fall as it exits the tube?
2 - once the marble leaves the tube, no more
force is exerted on it and it will continue in a
straight line.
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Applying Galileos idea of inertia
(b) The shuttle is drifting toward C in deep
space. If its rockets exert constant force in a
direction that is perpendicular to the drift,
what will the shape of the path be?
4 - constant thrust, means constant force, which
means continual acceleration.
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The End