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21 Cards in this Set

  • Front
  • Back
What are the 4 types of friction?
... sliding friction, rolling friction, static, and fluid friction.
What property of a surface or material describes its roughness or smoothness and affects the size of frictional force?
... texture.
What is friction?
a force that opposes the direction of motion of an object.
What is the weakest type of friction?
... fluid friction.
Lubricants reduce wear and tear on machinery by converting sliding friction in __________ friction.
... fluid
For friction to occur, two surfaces must be in ...
... contact.
What explains why a 2 kg block of wood with dimensions of 6cm x 12cm has more friction acting against it when slid along a table than another block with dimensions of 4cm x 6cm made of the same material and with equal mass?
... surface area.
What fluid frictional force opposes the motion of a falling object, sometimes causing it to fall more slowly than it otherwise would?
... air resistance.
Why is starting friction greater than sliding friction?
... because it must overcome the inertia of an object to put it in motion.
What is the strongest type of friction?
... sliding friction.
When does fluid friction occur?
... when an object moves through a liquid or a gas.
Friction is a _________ that opposes the direction of motion of an object.
... force
What property of an object related to its weight affects the size of friction?
... mass.
What produces rolling friction?
... wheels or ballbearings.
This property of an object to resist a change in its motion explains why starting friction is greater than sliding friction...
What can be applied to an object in motion to bring two surfaces in better contact that will also increase the amount of frictional force that is present?
... pressure.
Which is greater, starting friction or sliding friction?
... starting friction.
When does sliding friction occur?
... when two solids rub against eachother or slide over one another.
Lubricants reduce wear and tear on machinery by converting sliding friction into __________ friction.
... fluid
Friction always act in a direction that is ____________ to the direction of motion of an object.
... opposite
Why are lubricants such as oil used for moving machine parts?
... to reduce the amount of friction.