friction
TRANSCRIPT
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Daily Science1. If a book is sitting on a desk would it be a
balanced force or unbalanced force? Using arrows, show what forces are acting on the book.
2.How would you make the book become unbalanced if it’s balanced.
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Scenarios
What are the similarities between each scenario:
•You sitting in a chair
•Puck gliding across the rink
•Brakes stopping a car
•Football players colliding
•Tires screeching across the pavement
•Riding your bike
•Surfing on some killer waves
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What is friction?
• Friction is a force that two surfaces exert on each other when they rub against each other.
• What two factors do you think affect friction?
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Two factors that affect friction.
• The first factor is how hard the surfaces push together.
• Ex. Rubbing your hands together, the harder you rub your hands the warmer they get.
• The second factor is the types of surfaces involved.
• Would you rather rub your face with sand paper or wax paper?
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Types of Friction
• There are four types of friction:
1. Static Friction
2. Sliding Friction
3. Rolling Friction
4. Fluid Friction
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Static Friction
• Static Friction is when friction is acting on objects that aren’t moving.
• What could be some examples of this?
• Example: desk not moving, standing still, pencil laying on desk.
• The objects aren’t moving because of friction.
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Sliding Friction
• Sliding Friction occurs when two solid surfaces slide over each other.
• How can this be useful?
• Spreading sand on ice for more traction, using your brakes on your bike to stop.
• How can this not be useful?
• Slipping and falling on ice, falling off bike and skinning your knee.
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Rolling Friction
• Rolling friction is when objects roll across something. This provides rolling friction.
• What are some examples of rolling friction?
• Skateboard, rollerblades
• What do scientist use to reduce the amount of friction in wheels?
• They use ball bearings.
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Fluid Friction
• Fluid friction occurs when a solid object moves through a fluid.
• Some types of fluids are water, air, and oil.
• What are some examples of fluid friction?
• Surfing
• How is riding a bike an example of fluid friction.
• A cyclists cuts through the air.