Define types of friction.

Friction is the force that opposes motion between two surfaces that are in contact with each other. There are several types of friction:

• Static friction: This type of friction occurs when an object is at rest and an external force is applied to move it. Static friction opposes the applied force until the force is great enough to overcome it and the object starts to move.
• Kinetic friction: Also known as sliding friction, this type of friction occurs when two surfaces are in motion relative to each other. Kinetic friction opposes the motion of the object and slows it down.
• Rolling friction: This type of friction occurs when a round object, such as a ball or a wheel, rolls over a surface. Rolling friction is less than sliding friction, which makes it easier for objects to move.
• Fluid friction: Also known as air resistance or drag, this type of friction occurs when an object moves through a fluid, such as air or water. Fluid friction opposes the motion of the object and can be reduced by making the object more aerodynamic.
• Internal friction: This type of friction occurs within a material, such as the friction between molecules in a solid or the resistance to flow in a liquid. Internal friction can affect the behaviour of materials under stress or strain.