Friction and Gravity - ascsscience.weebly.com · •Sliding Friction-When solid surfaces slide over one another •Rolling Friction-When an object rolls along a surface •Fluid Friction-When
Post on 21-Dec-2018
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Friction and Gravity
Friction
• The force one object exerts on another when they move past each other
– Strength depends on:
• Types of surfaces involved
• How close the surfaces are to each other
• Example
Type of surface involved
• Imagine skiing or snowmobiling on bare ground…what would happen?
The type of surface determines friction
• Snow grips the skis less…
– Therefore there is less friction
• Dirt grips the skis more…
– Therefore there is more friction
– So much that it may cause
How hard surfaces push against each other
• The harder two surfaces push against eachother…the more friction is produced
– Atoms rubbing against each other
– Example
• Fish tank demo/Class demo
– Mass can increase friction
Useful Friction
• List some examples of how friction helps/doesn’t help you.
• You will be responsible for this on a test/quiz
Controlling Friction
• Sliding Friction-When solid surfaces slide over one another
• Rolling Friction-When an object rolls along a surface
• Fluid Friction-When an object moves through a liquid or gas
Sliding Friction
Rolling Friction
Fluid Friction
• Would skiing be an example of fluid friction, rolling friction or sliding friction?
• Would running be an example of fluid friction, rolling friction or sliding friction?
• Would dropping a rock in water be an example of fluid friction, rolling friction or sliding fricition?
Gravity
• Is a forces that pulls objects towards each other.
Free Fall
• When the only force acting on an object is gravity…an object is in free fall.
Projectile Motion
• Projectile-an object is launched horizontally
– Example
Air Resistance
• Fluid friction that deals with traveling though air
• Hand Planes
Weight vs. Mass
• Mass-How much matter is in an object
• Weight-The force of gravity pulling on an object
– Varies
– Weight =Mass x Acceleration due to gravity
Universal Gravitation
• States that the force of gravity acts on all objects in the universe
• You have gravity
• Strength depends on distance and mass
– Large close object=more gravity
– Small distant object=less gravity
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