Wheels Flashcards
Why does a wagon need wheels?
Friction opposes a wheel-less wagon’s motion
Why is sliding a box hardest at the beginning
Static friction is stronger than kinetic (sliding) friction, static friction’s maximum exceeds kinetic friction.
Static friction
opposes the start of sliding, it varies in amount from zero to a maximum value
Kinetic (sliding) friction
opposes ongoing sliding, it has a static constant value proportional to support force
What happens to energy as a box skids to rest?
That energy becomes thermal energy, only sliding friction wastes energy
Kinetic energy
energy of motion
Potential energy
stored in forces between objects
Thermal energy
disorder into tiny fragments, reassembling thermal energy is statistically impossible
How do wheels help a wagon coast?
Wheels can eliminate sliding friction, rollers eliminate sliding friction but don’t recycle, simple wheels have sliding friction at their hub/axle, combining roller bearings with wheels is ideal
What energy does a wheel have?
Kinetic energy, both translation and rational