Motion

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Motion
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Motion

• An object is in motion when its position changes.
• Position is the location of an object in space.
• Forces can make objects change their position.
• Gravitational force is the force that attracts 2
  objects. It increases as the objects masses
  increase.
• Friction is a force that opposes motion. It can
  prevent motion of slow it down.

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Example

• Think of a child sliding down a slide. Gravity
  pulls the child down the slide and friction slows
  the child down.
• If there was water on the slide the child would
  go faster because water reduces friction.

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Speed

• Speed is the distance an object travels in a
  certain amount of time.
• Speed is distance divided by time.
• Speed tells you how fast or slow something is
  moving.

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Velocity

• Velocity is the measure of an objects speed in a
  certain direction.
• Constant velocity occurs when something is moving
  at a constant speed.
• Velocity can change if the speed changes, the
  direction changes or both change.
• Velocity includes speed and direction.
• If a car is traveling in a circle at a constant
  speed, velocity is changing because the cars
  direction is changing.
• Velocity can change by stopping, slowing down,
  speeding up, and changing directions.

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Acceleration

• Acceleration looks at how quickly an object
  changes velocity.
• It is the rate at which velocity changes over
  time.
• When something speeds up, slows down, or stops
  you have acceleration.
• Acceleration deals with speed and direction.

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Momentum

• Describes how hard it is to slow down or stop an
  object.
• Momentum depends on mass and velocity.
• If a truck and a car is traveling at the same
  speed, the truck has more momentum because it has
  a greater mass.

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The Laws of Motion

• Newtons First Law of Motion
• Newtons Second Law of Motion
• Newtons Third Law of Motion

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Newtons First Law of Motion

• Describes inertia.
• Inertia deals with how an object resists any
  change in motion.
• No acceleration can happen without force. You
  must apply force to a ball like kicking it for it
  to move.
• According to Newtons First Law, when a car slows
  or stops suddenly, the people inside it continue
  to move. Seat belts apply force to prevent them
  from being hurt.

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Newtons Second Law of Motion

• First Law tells us that if we kick a ball it will
  move. The second law tells us that if we kick it
  harder, it will move faster.
• When force acts on an object, the object
  accelerates.
• An object accelerates depending on its mass and
  the force applied to it.
• It takes more force to push 5 shopping carts then
  1.

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Newtons Third Law of Motion

• Whenever one object applies force to a second
  object, the second object applies an equal and
  opposite force to the first object.
• Forces always occur in pairs.
• When 1 object pushes on another, the other object
  pushes back on the first.
• When you push a broom, the broom pushes back on
  you.
• When you jump on a trampoline, the trampoline
  pushes back on you.

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Sound Energy

• Sound is the form of energy that travels through
  the air.
• It is made when something vibrates.
• Vibration is a back-and-forth movement pf matter.
• When a drummer hits the drum, the head moves back
  and forth very quickly. As you hit harder, the
  decibels increase.
• The louder a sound is, the more energy being used.

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Sound Waves

• Sound travels through the air as waves.
• In order for a sound wave to form, matter must
  vibrate.
• The pitch of a sound is how high or low it is.
• Changing the length of a guitar string changes
  the pitch you hear.
• Frequency is the number of vibrations per second.
• A sound with a high frequency has a high pitch.
• Sound waves move out in all directions from the
  object that makes the sound.

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Sound Transmission

• When you knock down a line of dominos the first
  pushes the second and so on. Sound has energy
  that travels like dominos.
• The energy travels from place to place, but the
  matter that carries the energy stays where it is.
  
• When you talk to a friend vibrations move through
  the air from you to your friend.

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Formulas Examples

• Speed distance/time
• Accelerationchange in velocity/time
• Momentummass X velocity
• A snail travels 5 meters in 5 hours. What is the
  snails speed?
• A bubble rises in the air at a rate of 3km/hr.
  What is its velocity?
• Which factors determine momentum?

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Examples of the Reaction of Force
The road pushes on the motorcycle and the
motorcycle pushes on the road.
Object
If force pushes the object, the object will move
in the same direction as the force.
Force
If an object is falling, then the object pulls
the Earth. For example, if an orange is falling
from a tree then the orange is pulling the Earth.
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Questions

• What factors affect motion?
• What are the Laws of Motion?
• How do waves move?
• What are ways that velocity can be changed?
• Why are safety belts such an important safety
  feature in cars?