Force
6th Grade
Test Monday
Forces affect Motion
in Predictable Ways
Newton’s Laws
1st Law: Law of Inertia
2nd Law: F=ma
3rd Law: Action Reaction Law
Link To Newton’s 3 Law Review
Some Types of Forces
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Gravity
Friction
Weight
Thrust
Lift
Drag
Magnetism
Force
• A force is defined as an action on an object that
affects its motion (or lack of motion).
• The action is often called a push or pull. The push
can come from direct contact, like when objects
collide or from a force field like magnetism. The pull
seems to only come from a field at a distance, like
gravity or magnetism.
• The action from a force can cause an object to move
or speed up (accelerate), to slow down (decelerate),
to stop, or to change direction. Since any change in
velocity is considered acceleration, it can be said that
a force on an object results in the acceleration of an
object.
Physics of Flight
Link
Thrust
• Thrust is a force induced in the direction of
flight. It opposes the drag force.
To continue moving, an object must generate
enough thrust to equal the drag forces on it.
To accelerate, the thrust must exceed the
drag.
• Examples: engines, air from hover craft,
flapping of wings
• Uses Newton’s 3rd Law
Propulsion Page
Four principal propulsion systems: the propeller, the turbine (or jet) engine, the
ramjet, and the rocket.
Harrier Aircraft
can change direction of thrust
Weight
• Weight is a force that is caused by the pull of
gravity and is always directed towards the
center of Earth (at least if you are near Earth).
• Measured on a scale.
• Weight is different from mass. Mass is the
amount of matter (or stuff) something is made
of.
• Measured on a balance (triple beam balance).
Lift
• Lift is the force opposing the weight of the
object. An aerodynamic force. It always acts
perpendicular to a flying object.
• In a boat, it acts perpendicular to the wind
direction.
• Examples: wings of airplanes, gliders and
birds, parachutes, and sail of a boat
Drag
• Drag is the force that opposes the direction of
movement.
In a boat it works parallel to the wind
direction.
Something that slows the movement of an
object.
Gliders
Lift
Drag
Weight
NO THRUST
Friction
• Friction is a force that resists motion between
two touching surfaces.
It always acts opposite to the direction of the
motion.
Magnetism
• Magnetism is a force of attraction or repulsion
that acts at a distance. It is due to a magnetic
field, which is caused by moving electrically
charged particles or is inherent in magnetic
objects such as a magnet.
• A magnet is an object that exhibits a strong
magnetic field and will attract materials like iron
to it.
• Magnets have two poles, called the north (N) and
south (S) poles. Two magnets will be attracted by
their opposite poles, and each will repel the like
pole of the other magnet.
Maglev Train
Force and Motion in Action
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Airplanes
Rockets
Cars
Sports
Boats
Maglev Train
Formulas and Force
Speed = distance / time
s=d/t
Acceleration = (final Speed – initial Speed)/time
a=(sf-si)/t
Force = mass x acceleration
f=ma
Industry in Mississippi
Link to Putnamscienceonline.com
and Google Earth
Knowledge of Force and Motion is
used by Industry in Mississippi
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Ingalls Ship Yard
Nissan
Toyota
Raspet Flight Research Lab – MSU
Pioneer Aerospace
John C. Stennis Space Center
Link to Putnamscienceonline.com