Transcript Notes on Newton`s Laws of Motion

Notes on Newton’s Laws
11/07
Newton’s First Law of Motion
Newton’s First Law of Motion
• “The state of motion of an object does not
change as long as the net force acting on
the object is zero”
Newton’s First Law of Motion
• “The state of motion of an object does not
change as long as the net force acting on
the object is zero”
• What does this mean?
Newton’s First Law of Motion
• “The state of motion of an object does not
change as long as the net force acting on
the object is zero”
• What does this mean?
– If an object is at rest, it stays at rest
Newton’s First Law of Motion
• “The state of motion of an object does not
change as long as the net force acting on
the object is zero”
• What does this mean?
– If an object is at rest, it stays at rest
– If an object is moving, it keeps moving with
the same velocity
Newton’s First Law of Motion
• “The state of motion of an object does not
change as long as the net force acting on
the object is zero”
• What does this mean?
– If an object is at rest, it stays at rest
– If an object is moving, it keeps moving with
the same velocity
– This is called inertia (the tendency of an
object to resist a change in motion)
Newton’s Second Law of Motion
Newton’s Second Law of Motion
• “The acceleration of an object is equal to
the net force acting on it divided by the
object’s mass”
Newton’s Second Law of Motion
• “The acceleration of an object is equal to
the net force acting on it divided by the
object’s mass”
• Acceleration = net force/mass, or a = F/m
Newton’s Second Law of Motion
• “The acceleration of an object is equal to
the net force acting on it divided by the
object’s mass”
• Acceleration = net force/mass, or a = F/m
• Mass is the amount of matter in an object
and stays constant
Newton’s Second Law of Motion
• “The acceleration of an object is equal to
the net force acting on it divided by the
object’s mass”
• Acceleration = net force/mass, or a = F/m
• Mass is the amount of matter in an object
and stays constant
• Weight is the force of gravity on an object
and can change (W = mg)
Newton’s Second Law of Motion
• “The acceleration of an object is equal to
the net force acting on it divided by the
object’s mass”
• Acceleration = net force/mass, or a = F/m
• Mass is the amount of matter in an object
and stays constant
• Weight is the force of gravity on an object
and can change (W = mg)
– W = weight (in N)
Newton’s Second Law of Motion
• “The acceleration of an object is equal to
the net force acting on it divided by the
object’s mass”
• Acceleration = net force/mass, or a = F/m
• Mass is the amount of matter in an object
and stays constant
• Weight is the force of gravity on an object
and can change (W = mg)
– W = weight (in N)
– m = mass (in kg)
Newton’s Second Law of Motion
• “The acceleration of an object is equal to the net
force acting on it divided by the object’s mass”
• Acceleration = net force/mass, or a = F/m
• Mass is the amount of matter in an object and
stays constant
• Weight is the force of gravity on an object and
can change (W = mg)
– W = weight (in N)
– m = mass (in kg)
– g = acceleration due to gravity – on earth,
this is 9.8 m/s2
Newton’s Third Law
Newton’s Third Law
• “whenever one object exerts a force on a
second object, the second object exerts an
equal and opposite force on the first
object.”
Newton’s Third Law
• “whenever one object exerts a force on a
second object, the second object exerts an
equal and opposite force on the first
object.”
• In other words: “for every action, there is
an equal and opposite reaction”