Transcript Explain the First Law of Motion

Newton’s Laws
of
Motion
Explain the
First Law of Motion
Explain the First Law of
Motion
• An object will not change its
motion unless a force acts on it.
• An object that is not moving
remains at rest until something
pushes or pulls it.
• An object that is moving remains
moving until something pushes or
pulls it.
Explain the First Law of
Motion
• The force that causes objects to
slow down is FRICTION.
• Friction always acts opposite to
the direction of motion.
• To keep an object moving when
friction is acting on it, you have
to keep pushing or pulling on the
object to overcome the
frictional force.
Explain the First Law of
Motion
• All objects resist having their
motion changed.
• This tendency to resist a change
in motion is called inertia.
• The more mass an object has,
the greater its inertia.
See Examples of the 1st Law
of Motion Here:
http://www.jracademy.com/~m
basteaf/newton/first/index.ht
ml
Review the First Law here:
http://www.usoe.k12.ut.us/cur
r/science/sciber00/8th/forces
/sciber/newtons.htm
More information about
Newton’s First Law of
Motion may be found
here:
http://www.beyondbooks.com/
psc91/4a.asp
Explain the
Second Law of Motion
Explain the Second Law of
Motion
• A change in motion occurs only if
a net force is exerted on an
object.
• A net force changes the velocity
of the object, and causes it to
accelerate.
Explain the Second Law of
Motion
• If an object is acted upon by a net
force, the change in velocity will be in
the direction of the net force.
• Acceleration can be calculated from
the formula:
Explain the Second Law of
Motion
• The acceleration of an object
depends on its mass.
• The more mass an object has or
the more inertia it has, the
harder it is to accelerate.
• More mass means less acceleration if
the force acting on the objects is the
same.
Explain the Second Law of
Motion
• If a stands for the acceleration,
Fnet for the net force, and m for the
mass, this formula can be written as
follows:
• In this formula the force is in
newtons, the mass is in kilograms, and
the acceleration is in meters per
second squared.
See Examples of the 2nd Law
of Motion Here:
http://www.jracademy.com/~m
basteaf/newton/second/index.
html
Review the Second Law
here:
http://www.usoe.k12.ut.us/cur
r/science/sciber00/8th/forces
/sciber/newton2.htm
More information about
Newton’s Second Law of
Motion may be found here:
http://www.beyondbooks.com/
psc91/4d.asp
Explain the
Third Law of Motion
Explain the Third Law of
Motion
• When one object exerts a force
on a second object, the second
object exerts an equal force in
the opposite direction on the
first object.
• The force exerted by the first
object is the action force.
• The force exerted by the second
object is the reaction force.
See Examples of the 3rd Law
of Motion Here:
http://www.jracademy.com/~m
basteaf/newton/third/index.ht
ml
Review the Third Law
here:
http://www.usoe.k12.ut.us/cur
r/science/sciber00/8th/forces
/sciber/newton3.htm
More information about
Newton’s Third Law of
Motion may be found here:
http://www.beyondbooks.com/
psc91/4f.asp