1. What is friction? 2. On what principle do ball bearings work? 3. How does lubrication reduce friction? 4. An object is moving from north to south. What is the direction of the force of friction on the object?
Answer (1)
What is friction?
Friction is a force that opposes the relative motion or tendency of such motion of two surfaces in contact. It acts parallel to the surfaces and opposite to the direction of motion. Friction arises from the interactions between the surfaces, including microscopic irregularities and intermolecular forces.
On what principle do ball bearings work?
Ball bearings work on the principle of reducing friction between a rotating shaft and the housing it sits in. Instead of having surfaces in contact slide against each other, ball bearings introduce spherical balls that roll, thereby converting sliding friction into rolling friction, which is significantly lower. The balls rotate, minimizing the frictional force that acts on the moving parts.
How does lubrication reduce friction?
Lubrication reduces friction by creating a thin film between the surfaces in contact. This film can be made of liquid, grease, or some other material that allows the surfaces to slide over each other more easily, reducing direct contact and consequently the frictional force. Lubrication also helps reduce wear and heat generated by friction.
An object is moving from north to south. What is the direction of the force of friction on the object?
The direction of the force of friction is opposite to the direction of motion. Therefore, if the object is moving from north to south, the force of friction is directed from south to north.
