Which of the following produces the least friction?

Rolling friction

Rolling friction produces the least friction.

Friction is the force that opposes the relative motion of two surfaces in contact. There are three main types of friction: static friction, sliding friction, and rolling friction. Among these:

1. Static Friction: This occurs when an object is at rest and resists motion. It is the strongest type of friction.
2. Sliding Friction: When an object slides over a surface, the resistance is lower than static friction but still significant.
3. Rolling Friction: When an object rolls over a surface (like a wheel or ball), the area of contact is smaller, and the resistance is minimal compared to sliding or static friction.

The reason rolling friction is the least is due to the reduced area of contact between the rolling object and the surface. This minimizes the interlocking of irregularities between the two surfaces, reducing resistance.

Example:

A car with round tires (rolling friction) moves more easily than dragging a sled on the ground (sliding friction). This is why wheels and rollers are widely used to reduce friction and improve efficiency in machines.