The coefficient of static friction between two surfaces depend on

Options

A. nature of surface
B. the shape of the surface in contact
C. the area of contact
D. all of the above

Explanation

To solve the question regarding the coefficient of static friction between two surfaces, we need to analyze the factors that influence it. Here’s a step-by-step breakdown:

### Step-by-Step Solution:

1. **Understanding Friction**:
- Friction is a resistive force that opposes the relative motion between two surfaces in contact.
- Static friction specifically refers to the frictional force that must be overcome to start moving an object at rest.

2. **Coefficient of Static Friction**:
- The coefficient of static friction (denoted as μs) is a dimensionless value that represents the ratio of the maximum static frictional force (Fs) to the normal force (N) acting between the surfaces.
- Mathematically, it is expressed as:
\[ \mu_s = \frac{F_s}{N} \]

3. **Factors Affecting the Coefficient of Static Friction**:
- The coefficient of static friction depends primarily on the **nature of the surfaces** in contact. This includes:
- The materials of the surfaces (e.g., rubber on concrete, wood on wood).
- The texture of the surfaces (smooth vs. rough).
- It does **not depend on**:
- The shape of the surfaces in contact (whether they are circular, cuboidal, etc.).
- The area of contact between the surfaces (as long as the surfaces are in contact, the coefficient remains the same).

4. **Conclusion**:
- Therefore, the coefficient of static friction between two surfaces depends on the nature of the surfaces in contact.

### Final Answer:
The coefficient of static friction between two surfaces depends on the nature of the surfaces.

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