Why is it easier to move boxes on a wheeled dolly than by sliding them?
more total work
starting friction
increase surface tension
rolling friction
Rolling friction is friction that acts on objects when they are rolling over a surface. Rolling friction is much weaker than sliding friction or static friction. This explains why it is much easier to move boxes on a wheeled dolly than by carrying or sliding them. It also explains why most forms of ground transportation use wheels, including cars, 4-wheelers, bicycles, roller skates, and skateboards. Ball bearings are another use of rolling friction (see Figure below ). They allow parts of a wheel or other machine to roll rather than slide over one another.