Transcript 4-2 Newton’s First Law

11.1 Newton’s First Law
INERTIA
An object at rest remains at rest,
and an object in motion
maintains its velocity unless it
experiences an unbalanced
force
Stationary objects don’t
want to move
Moving objects
don’t want to stop
Mass is a measurement of inertia
More mass =
more inertia
Therefore mass
which is a measure
of the amount of
matter in an object
is also a measure
of the inertia of an
object
When you are in a car that is accelerating,
you feel like you are being pushed back.
When the car comes to a sudden stop,
your body wants to continue in a forward
motion.
Your body’s inertia is
resisting the change in
speed.
When stopping,
the coffee tends
to spill forward
When accelerating,
the coffee tends to
spill on you.
Sudden Stops seat belts help your
body resist the
tendency to keep
moving.
Sudden Starts head rests stop the
head from being
pushed back.
What will happen without seatbelt?
What happens when you stop applying a
Misconception!! force to an object?
- If no force acts on a moving object,
it will eventually come to rest.
- Motion requires the presence on a force.
Truth!!
- Only a force can cause a change in the
motion of a moving object.
- An object moves at a constant
velocity or not at all if there is no
force acting on it.