Wheels

Question 1

Why does a wagon need wheels?

Answer 1

Friction opposes a wheel-less wagon’s motion

Question 2

Why is sliding a box hardest at the beginning

Answer 2

Static friction is stronger than kinetic (sliding) friction, static friction’s maximum exceeds kinetic friction.

Question 3

Static friction

Answer 3

opposes the start of sliding, it varies in amount from zero to a maximum value

Question 4

Kinetic (sliding) friction

Answer 4

opposes ongoing sliding, it has a static constant value proportional to support force

Question 5

What happens to energy as a box skids to rest?

Answer 5

That energy becomes thermal energy, only sliding friction wastes energy

Question 6

Kinetic energy

Answer 6

energy of motion

Question 7

Potential energy

Answer 7

stored in forces between objects

Question 8

Thermal energy

Answer 8

disorder into tiny fragments, reassembling thermal energy is statistically impossible

Question 9

How do wheels help a wagon coast?

Answer 9

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

Question 10

What energy does a wheel have?

Answer 10

Kinetic energy, both translation and rational