______leads to rolling friction instead of sliding friction, which further reduces friction

Options

A. Wheels
B. Ball bearings
C. Lubricants
D. Oil

Answer

To solve the question, we need to identify what leads to rolling friction instead of sliding friction, which further reduces friction.

### Step-by-Step Solution:

1. **Understanding Friction Types**:
- Friction can be classified into two main types: sliding friction and rolling friction. Sliding friction occurs when two surfaces slide against each other, while rolling friction occurs when an object rolls over a surface.

2. **Identifying the Options**:
- The options given are:
- A) Ball-bearing
- B) Lubricants and oils
- C) Wheels
- D) None of the above

3. **Analyzing Each Option**:
- **Option A: Ball-bearing**:
- Ball-bearings are designed to reduce friction between moving parts. They allow for rolling motion instead of sliding, which converts sliding friction into rolling friction. This is achieved by having small balls that roll between the surfaces, reducing contact area and friction.
- **Option B: Lubricants and oils**:
- While lubricants and oils reduce friction, they do not specifically convert sliding friction into rolling friction. They work by creating a slippery layer between surfaces, thus reducing overall friction but not changing its type.
- **Option C: Wheels**:
- Wheels inherently have rolling friction. However, they do not lead to rolling friction from sliding friction; they are already designed for rolling. Therefore, they do not fit the question's requirement.
- **Option D: None of the above**:
- This option can be disregarded since we have identified a suitable option.

4. **Conclusion**:
- The correct answer is **Option A: Ball-bearing**, as it specifically leads to rolling friction instead of sliding friction, effectively reducing friction.

### Final Answer:
**Ball-bearing leads to rolling friction instead of sliding friction, which further reduces friction.**