Which of the following statements is correct about friction?

Options

A. The coefficient of friction between a given pair of substances is largely independent of the area of contact between them.
B. The frictional force can never exceed the reaction force on the body from the support surface.
C. Rolling friction is only slightly smaller than slidmg friction.
D. The main source of friction is the irregularity of the surfaces in contact.

Explanation

To determine which statement about friction is correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: The coefficient of friction between a given pair of substances is largely independent of the area of contact between them.**
- The coefficient of friction (µ) is defined as the ratio of the frictional force (F) to the normal reaction force (R). Mathematically, it is expressed as:
\[ \mu = \frac{F}{R} \]
- This relationship indicates that the coefficient of friction is independent of the area of contact. Therefore, this statement is **true**.

2. **Statement 2: The frictional force can never exceed the reaction force on the body from the support surface.**
- The frictional force can be expressed as:
\[ F = \mu \cdot R \]
- If the coefficient of friction (µ) is greater than 1, theoretically, the frictional force can exceed the normal reaction force (R). Hence, this statement is **incorrect**.

3. **Statement 3: Rolling friction is only slightly smaller than sliding friction.**
- In reality, rolling friction is generally much smaller than sliding friction. This statement is misleading and therefore **incorrect**.

4. **Statement 4: The main source of friction is the irregularity of the surfaces in contact.**
- While surface irregularities do contribute to friction, the primary factor affecting friction is the nature of the materials in contact, including their properties. Thus, this statement is also **incorrect**.

### Conclusion:
From the analysis above, the correct statement about friction is:
- **Statement 1**: The coefficient of friction between a given pair of substances is largely independent of the area of contact between them.