Answer:
→ Friction resists motion
→ Friction is a contact force.
→ Friction is caused by microscopic bumps and ridges on surfaces.
Explanation:
As the normal force, the friction is a contact force because it result when two objects interact by a direct contact, that is, touching to each other. Friction is important in everyday life and resists motion. For example, the oil in a car engine minimizes friction between moving parts, but a car can move because the friction between the tires and the road, but what about the microscopic level? well, as the normal forces friction forces result from the intermolecular forces between two rough surfaces at points where they come into contact and they are electrical in nature.
