Download Force and Motion

Potential vs. Kinetic
 Potential
 * GPE
 * stored energy
 * not moving
 * the higher the object
the more PE
 * GPE=mgh
G= 9.8 m/s2
Kinetic
* KE
* energy of motion
* moving
* the faster an object
the more KE
* KE=mv2
Mechanical vs. Chemical
 Mechanical
Chemical
• ME = PE+KE
• Physical change
• Only changes the physical
appearance
• Ex. Gears moving in a car
• Energy that is moving
* Chemical change
* changes the
composition
* Ex. food being broken
down
* energy that is stored
Types of Energy
 Electrical: energy that is transferred by electrical charges
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or current
Sound: associated with vibrations of matter and requires
an object to travel through (Medium). Ex. Water
Solar: the energy given off by the sun
Chemical: energy that is stored in the chemical
composition of matter
Thermal: the energy given off my heat
Light: energy given off by light
Nuclear: the potential energy stored in the nucleus of an
atom
Simple Machines
Type
Definition
Example
Lever
A solid bar that
rotates around
a fulcrum
Inclined Plane
A flat horizontal
or sloped ramp
Pulley
A wheel that
turns on an axle
Handicap
ramp
Crane,
gears
Wheel & Axle
A wheel that is
fixed to a pulley
Car or
gears
Wedge
2 incline
planes that are
together
screwdriver
Screw
An incline plane
wrapped around
a shaft
Spiral stairs
or meat
grinder
Wheelbarrow
Illustration
Force and Motion Important Terms
 Position: location (can be an object or place)
 Reference Point: location that you compare your
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object or place’s position
Motion: change of position over time
Speed: the measure that something moves in a given
amount of time s=distance over time
Velocity: speed in a specific direction
Acceleration: the rate at which velocity changes with
time
Force and Motion Important Terms
 Friction: force that resists the motion between two
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surfaces in contact.
Force: a push or pull (F= M x A)
Balanced force: net force is zero, the motion of an
object does not change
Unbalanced force: changes the motion of an object
Inertia: the resistance of an object to a change in the
speed or direction of its motion
Newton’s
st
1
Law of Motion
 An object at rest stays at rest, and an object in motion
stays in motion at the same velocity, unless acted upon
by an unbalanced force.
 Newton’s First Law is also called the Law of Inertia.
 Inertia is closely related to mass. When you measure the
mass of an object, you are also measuring its inertia.
 The more mass something has, the harder it is to change its
motion.
 Ex: It’s easier to stop an empty wagon than a wagon full of
sand.
nd
2
Law of Motion
 Acceleration of an object increases with increased force and
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decreases with increased mass.
The direction in which an object accelerates is the same as the
direction of the force.
Simply put: Newton’s Second Law is…
F = ma
(Force = mass x acceleration)
The standard unit of force is the newton (N).
Because force = mass x acceleration, force is measured in units of
mass (kg) times units of acceleration (m/s2).
A newton is the amount of force that it takes to accelerate 1 kg of
mass 1 m/s2.
So…. I N = 1 kg x 1 m/s2.
rd
3
Law of Motion
 Forces always act in pairs!
 Newton’s Third Law: For every action, there is an
equal and opposite reaction.
 Every time one object exerts a force on another
object, the second object exerts a force that is
equal in size and opposite in direction back on the
first object.
Summary of Newton’s 3 Laws
Distance/Time Graphs
The motion of an object can be represented in a line graph. The data table
below charts the motion of an object in 20 seconds.
Construct a line graph on page 28 (blank page) that shows the motion of
the object. Be sure to label both axes.
Then, use the graph to describe the motion of the object between 0 and 10
seconds.
Distance vs. Time
Time (s)
0
5
10
15
20
Distance
(m)
0
10
10
15
20