Increase frictional force: Rough surface, More mass, Patterned and rough shoes soles, Treaded tyres, Anti-slip mat, Easier to stop, Decrease frictional force: Smooth surface, Less mass, Lubricating oil, Wheels , Can move further, Can move faster,

per en/la

Tauler de classificació

Estil visual

Opcions

Canvia de fonament

Restaurar desada automàtica: ?