Transcript A Frictionless world

A Frictionless world
A Discussion of how this fits in with Newton’s
first law of motion

What happens in a world without friction?
What did you notice happening when an
object did not interact with anything?

It keeps going in a straight line

What happens when it comes in contact
with a force?
 It changes it’s motion (slows down, speeds
up, changes direction)
This is Newton’s First Law of
Motion
An object at rest remains at rest and an
object in motion remains in motion at
constant speed and in a straight line
unless acted on by an unbalanced
force.
We can break his law into two
parts:

Part 1: Objects at rest
 Part 2: Objects in motion
 Bumper
car analogy
What the law really means.
 Objects moving
at a certain velocity will continue to
move forever at the same speed and in the same
direction unless some unbalanced force acts on it.
 If
that’s the case, you should be able to give your
table a shove and send it flying across the room.
 But does this happen?
 No.
 Because
of this observation, Aristotle thought that
all objects wanted to be at rest.
 It
was Newton who examined Aristotle’s thinking
and took into account the force due to friction which
helped him formulate his First Law of motion. If
friction is not present, then an object would continue
the same path forever.
Dry Ice demo:

Play with the dry ice. Allow it to sit for a few
minutes on top of the table. It is an object at rest.
Carefully give your dry ice a shove with a spoon
to set it in motion and watch it’s motion across the
table. Draw it’s path in your notebook. While the
dry ice is still in motion, tap the dry ice and
describe what happens to it’s motion in words and
with a picture.
Newton’s First law is often
summed up in one sentence:

Matter resists any change in motion.
 The tendency of all objects to resist any
change in motion is called inertia.
 Mass is a measure of inertia