13.2 Frictional force
What is the relationship between frictional force, the movement of objects and energy?
When an object moves over a surface, there is frictional force or friction between the surface and the object. Friction causes a moving object to slow down and stop.
The larger the mass of an object, the harder the object presses on a surface. Thus, there is more friction.
The type of surface also affects friction and movement. There is more friction between an object and a rough surface than between the same object and a smooth surface.
(a) The bigger bicycle has a larger mass than the smaller bicycle. Thus, there is more friction between the bigger bicycle and the road.
(b) There is more friction between a moving car and the normal and rough road. This allows the driver to move and stop the car safely.
(c) There is less friction between a moving car and the slippery and smooth road. This makes it difficult to stop the car safely.