Transcript Newton`s First Law of Motion What it says: An object at rest will

Newton’s First
Law of Motion
Newton’s First Law of Motion
What it says:
An object at rest will remain at rest and an object in
motion will remain in motion at constant speed and
in a straight line unless acted on by an unbalanced
force.
What it means:
Unless you apply force to a
What it means:
stationary object it will
Unless you
force
to a stationary
notapply
move.
Likewise,
unless object it
will not move.
force is applied to a
moving object it will not
Likewise,
unless
force
is applied
stop
moving
nor
will it to a
moving object
will not stop
changeitdirections.
It moving
tends nor will it
change directions.
tends
to do what it was
to do what It
it was
doing
doing unless
force
is applied
to to
it it.
unless
force
is applied
How does motion occur?
In order to understand how motion occurs you must
first understand what force is.
FORCE is an action that has the ability to change
motion.
I you were asked to move your desk to another place
in the room, how would you do that?
Most of you probably are saying pick it up and carry it,
drag it across the room, or push it across the room.
In using any method to move the desk, there are only
two ways in which force can be applied to the desk
to cause it to move. What are they?
You either PUSH IT or PULL IT.
The metric unit for force is the Newton.
1 N = 1 kg x 1 m/sec2
This means that a force of 1 N will cause a 1 kg
mass to accelerate at a speed of 1 m/sec2
Unless force is applied to an object, that object
will never move. This force must be in sufficient
quantity or strength to overcome the mass of the
object that is being moved. Nothing moves on its
own. The force must over come the force of friction.
Unless the bowling ball strikes
the pins, they will never move.
Balanced Forces: The forces on an object
are equal in size but opposite in direction;
will not change the objects velocity.
Ex) A tug of war when no team is winning.
Unbalanced Forces: Occur when one force on an
object is stronger than another; will change an objects
velocity.
Ex) A tug of war when one team is winning.
Friction is the force that opposes the sliding motion of two
surfaces that are touching one another.
The rougher the two surfaces the higher the friction force.
The higher the force pushing the surfaces together the
higher the friction force.
Newton’s First Law is also known as the Law of Inertia.
Inertia is a property of mass. Simply defined,
inertia is the resistance of an object to a change
in its motion.
Which would require more force to move?
WHY?
The donkey
has more
mass
__________.
Therefore, it has more
inertia
_____________.
The > the mass the > the inertia.
REVIEW
An object at rest will remain at rest and an object
in motion will remain in motion at constant speed
and in a straight line unless acted on by an outside
force.
Inertia is the resistance of an object to a change in
its motion.
The > the mass the > the inertia.
The
End