Download Newton`s Laws of Motion

NEWTON'S LAWS OF
MOTION
BATTEN
BARR
FORCE
• A push or a pull
• SI unit is newtons (N)
• 1 newton = the amount of force it takes to lift a quarterpound hamburger
• Changes an objects motion
FORCES
• Balanced Forces – when the effects of two or more
forces cancel each other
• Unbalanced Forces – when the effects of the forces
do not cancel each other
• The combination of the forces is the net force.
NEWTON’S 1ST LAW
• An object in motion stays in motion and an object
at rest stays at rest
• Unless acted on by an unbalanced force!
• Outside forces include
• A push or a pull
• Running into something
• Friction
• Friction is a force between 2 surfaces in contact
that resists the motion
• This causes moving objects to slow down.
• Acts in the direction opposite the motion.
• Inertia is the tendency to resist a change in motion
• The more mass – the more inertia
NEWTON'S 2ND LAW
• A change in motion occurs only if a net forces is
exerted on an object
• The acceleration is in the direction of the net force.
• Net Force= Mass x Acceleration
• The more mass of an object = more force needed
to accelerate the object.
• Which cart needs more force to accelerate?
NEWTON’S 3RD LAW
• For every action, there is an equal and opposite
reaction.
• Force exerted by the first object is the action force
• Force exerted by the second object is the reaction
force.
• Example: a swimmer pushing off a wall
• Swimmer exerts the action force
• The wall exerts the reaction force.
KEPLER’S 3 LAWS
• 1st law - sometimes referred to as the law of ellipses
- explains that planets are orbiting the sun in a path
described as an ellipse
• 2nd law - sometimes referred to as the law of equal
areas - describes the speed at which any given
planet will move while orbiting the sun.
• 3rd law - sometimes referred to as the law of
harmonies- compares the orbital period and radius
of orbit of a planet to those of other planets
Newton was able to show that his
laws of gravitation gave the same
results as Kepler's. In fact, Newton
was able to take things farther with
his strong math background to show
that the shape of the orbits were
conic sections (for those of you that
have seen that stuff in math).
MACHINES
• What is a machine?
• a device that makes work easier
• Simple machine – uses one movement
• List/draw the types of simple machines
• Compound machine - combination of simple machines
MECHANICAL ADVANTAGE
• Number of times a machine increases the force
applied to it
• Output force (Fo)
Input force (Fi)
•
• MA = Fo / Fi
•
MA = 1
MA > 1
good
really good