This document discusses the history of the concept of inertia. It describes how Aristotle rejected the idea of inertia and believed that a constant force was needed to maintain motion. Galileo conducted experiments rolling balls down ramps and found that their rate of descent remained constant regardless of size, showing uniform acceleration. Descartes proposed three laws of nature, including that an object remains in the same state of motion unless acted on by an unbalanced force. The document also provides materials and procedures for demonstrating inertia by pulling paper out from under objects.

2. Brief History
Aristotle
He rejected the notion of inertia,
asserting instead that a force must
be constantly applied to keep something moving.

3. Galileo Galilei
He made experiments involving bronze balls of
various sizes rolling down an inclined wood plane.
Galileo recorded how far a ball would roll in each
one-second interval. He found that the size of the
ball didn't matter -- the rate of its descent along the
ramp remained constant.
From this, he concluded that freely falling objects
experience uniform acceleration regardless of mass,
as long as extraneous forces, such as air resistance
and friction, can be minimized.

4. René Descartes
In his "Principles of Philosophy," Descartes
proposed three laws of nature.
The first law states: "that each thing, as far
as is in its power, always remains in the
same state; and that consequently, when it is
once moved, it always continues to move."
The second holds that "all movement is, of
itself, along straight lines."

5. Also called Law of Inertia

6. Materials
• one large piece of smooth paper
• one book with a hard, glossy cover
• objects to place on the paper
Procedures
1. Place the piece of paper on a flat, smooth surface.
2. Put the book with the glossy cover on top of the
paper.
3. Quickly (and in one smooth motion) yank the paper
out from under the book.
4. Do the activity again, this time putting other objects
on top of the book. Observe what happens.

7. Inertia
the natural tendency to resist changes
in the state of motion)

8. Unbalanced Force
Forces are unequal in magnitude, the
resultant is zero thus producing an
acceleration

9. Mass
One factor that make up inertia
because the more mass an object
has the more inertia that object will
pass

10. MASS is the quantity of matter in
an object while WEIGHT is the
force of gravity on an object.