Download Newton`s Laws of Motion

Newton’s Laws of Motion
The concepts of force and motion are evident in
everyday life.
You will learn how to investigate and describe
applications of Newton’s laws such as in
vehicle restraints, sport activities, geological
processes, and satellite orbits.
FORCE
• What is force?
• Force is the push or pull that one object
exerts on another.
Newton’s First Law of Motion
Law of Inertia
• An object will remain at rest or in motion
unless acted upon by an outside force.
• If it is moving it will continue to move; if it
is at rest (still) it will remain at rest.
Newton’s 2nd Law of Motion
• The unbalanced force acting on an object
equals the object’s mass times its
acceleration.
Force = mass X acceleration
• F = newtons
• M = kilograms
• A = m/s
FORCE
• What is the force?
Sample Question
How much force is needed to accelerate a
1,300 kg car at a rate of 1.5 m/s2?
A. 867 N
B. 1950 N
C. 8493 N
D. 16562 N
nd
2
Law
F= m x a
A speeding bullet and a slow moving train both have tremendous force.
The force of the bullet is caused by its incredible acceleration while the
force of the train comes from its great mass.
Free Fall and Weight
• Free Fall – the motion of a body when only the force
of gravity is acting on it.
• Free fall or acceleration due to gravity is abbreviated
[g] and it is equal to 9.8 m/s2.
• Weight = mass X acceleration due to gravity
• Terminal velocity – the maximum velocity reached
by a falling object that occurs when the resistance of the
object is equal to the force due to gravity.
Newton’s 3rd Law of Motion
• For every action force, there is an equal
and opposite reaction force.
Friction
• Friction is a force that opposes motion.
• Friction acts in a direction opposite to the
object's direction in motion.
• Without friction, the object would continue
to move at a constant speed forever.
http://www.usoe.k12.ut.us/curr/science/sciber00/8th/forces/sciber/intro.htm
Air Resistance
• Air resistance is friction between an object and the air
molecules.
• What will fall faster, an elephant or a feather if there is no
air resistance (friction with the air molecules)?
No Air Resistance
With Air Resistance
Air Resistance (cont.)
Which encounters
the greater force
of air resistance—
1. A falling
elephant, or
2. A falling
feather?