**Friction always works in the opposite direction of motion of the surface.**

Friction is a force that opposes the motion of an object when it is in contact with another object or surface. It acts in the opposite direction to the applied force, which means it always works in the opposite direction of the motion of the surface. This statement is true and can be explained in detail using the following points:

**Definition of Friction:**
Friction is the force that occurs when two objects or surfaces come into contact and move against each other. It is a resistance force that opposes the relative motion or tendency of motion between the two surfaces.

**Opposes Motion:**
Friction always opposes the motion of an object. When an external force is applied to move an object, friction acts in the opposite direction to this applied force. For example, if you push a box to the right, the frictional force acts to the left, opposing your push.

**Surface Interaction:**
Friction occurs due to the interaction between the surfaces in contact. When two surfaces are in contact, irregularities or roughness on the surfaces interlock or come in contact with each other. This interlocking or contact creates a resistance force that opposes the motion between the two surfaces.

**Types of Friction:**
There are different types of friction, namely static friction, sliding friction, and rolling friction. Each type of friction acts in the opposite direction of the motion.

- Static Friction: This is the friction that opposes the initial motion of an object. When an object is at rest and an external force is applied to move it, static friction prevents the object from moving until the applied force overcomes the maximum static friction. Static friction always acts in the opposite direction of the impending motion.

- Sliding Friction: Sliding friction occurs when two surfaces slide against each other. It acts in the opposite direction of the sliding motion. For example, when you slide a book on a table, the frictional force between the book and the table acts to oppose the sliding motion.

- Rolling Friction: Rolling friction occurs when an object rolls over a surface. It acts in the opposite direction of the rolling motion. For instance, when a ball rolls on the ground, the frictional force between the ball and the ground acts to slow down the rolling motion.

**Conclusion:**
Friction is a force that always works in the opposite direction of the motion of the surface. It opposes the motion and acts as a resistance force. Whether it is static friction, sliding friction, or rolling friction, the frictional force always acts in opposition to the motion.

Friction always opposes the relative motion between two surfaces,so the answer is true.