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Newton’s first law of motion: Friction8SCIENCE
Types of friction• What is friction?– Unbalanced force that slows objects down
• Important to understand to use Newton’s laws as friction in almost all real-life situations
Types of friction:• Static friction• Sliding friction• Rolling friction• Air resistance
Static friction
• Friction prevents an object from moving when force is applied
• Tries to keep an object at rest• Ex: walking– Every step you take pushes
against the Earth– Without friction, you would
slip and fall with each step
• What happens when the net force is greater then the force of static friction?
Sliding friction
• Slows down an object that slides• Ex: if you push a box across the room, there is
sliding friction between the bottom of the box and the floor
• Ex: Rubbing hands , shuffling shoes
Types of Friction
ROLLING FRICTION• Allows wheels to turn by
pushing back so tire moves forwards– Ex: bicycle, car
• Ex: when you ride your bike through water, there may not be enough friction between the tire and the ground to move forward, and so the bike skids (slides off balance)
AIR RESISTANCE• Air pushes against you• Acts on the forward-moving
part an object– Ex: front of a car
• Ex: when you ride the bicycle, the air pushes the your hair and clothes back