Define frictional force (or friction).
Frictional Force refers to the force generated by two surfaces that contacts and slide against each other. These forces are mainly affected by the surface texture and amount of force impelling them together. The angle and position of the object affect the amount of frictional force.
If an object is placed flat against an object, then the frictional force will be equal to the weight of the object.
If an object is pushed against the surface, then the frictional force will be increased and becomes more than the weight of the object.