Smooth surface has_________

Options

A. less frictional force
B. more frictional force
C. sometimes less and sometime more force
D. no frictional force at all.

Explanation

To answer the question "Smooth surface has_________", we need to analyze the options provided and understand the concept of friction in relation to smooth surfaces.

### Step-by-Step Solution:

1. **Understanding Friction**:
- Friction is the force that opposes the relative motion of two surfaces in contact. The amount of friction depends on the nature of the surfaces and the normal force acting between them.

2. **Analyzing the Options**:
- **Option 1: Less frictional force**: This suggests that a smooth surface has a lower resistance to motion.
- **Option 2: More frictional force**: This implies that smooth surfaces create more resistance, which contradicts the definition of smoothness.
- **Option 3: Sometimes less and sometimes more force**: This suggests variability in friction, which is not characteristic of smooth surfaces.
- **Option 4: No frictional force at all**: This implies a complete absence of friction, which is practically impossible since all surfaces have some degree of roughness.

3. **Evaluating Each Option**:
- **Option 4** is incorrect because no surface is perfectly smooth; there is always some friction.
- **Option 3** is also incorrect because a smooth surface consistently provides less friction, not variable friction.
- **Option 2** is incorrect as smooth surfaces do not create more friction.
- **Option 1** is correct because smooth surfaces are characterized by having less frictional force, allowing objects to slide more easily.

4. **Conclusion**:
- Therefore, the correct answer is: "Smooth surface has less frictional force."

### Final Answer:
Smooth surface has **less frictional force**.