Consider the following statemnts
When applied force F exceeds`(f_s)_max` the body begins to slide on the surface
When relative motion has started frictional force decreases from`(f_s)_max`.Choose the correct option

Options

A. Only statement I is correct
B. Only statement II Is correct
C. Both statements I and II are correct
D. None of the above

Answer

To solve the question, we need to analyze the two statements regarding friction:

1. **Statement 1**: When the applied force \( F \) exceeds \( (f_s)_{max} \), the body begins to slide on the surface.
2. **Statement 2**: When relative motion has started, the frictional force decreases from \( (f_s)_{max} \).

### Step-by-Step Solution:

**Step 1: Understanding Static Friction**
- Static friction is the force that prevents an object from moving when a force is applied. The maximum static friction force is denoted as \( (f_s)_{max} \).
- The object will remain at rest as long as the applied force \( F \) is less than or equal to \( (f_s)_{max} \).

**Step 2: Analyzing Statement 1**
- According to the first statement, if the applied force \( F \) exceeds \( (f_s)_{max} \), the static friction can no longer hold the object in place, and it will start to slide.
- This statement is **correct** because it accurately describes the transition from static to kinetic friction.

**Step 3: Understanding Kinetic Friction**
- Once the object starts sliding, static friction is no longer applicable; instead, kinetic friction comes into play.
- Kinetic friction is usually less than the maximum static friction, meaning the frictional force acting on the sliding object will be lower than \( (f_s)_{max} \).

**Step 4: Analyzing Statement 2**
- The second statement claims that when relative motion has started, the frictional force decreases from \( (f_s)_{max} \).
- This is also **correct** because once the object is in motion, the frictional force acting on it is the kinetic friction, which is less than \( (f_s)_{max} \).

**Step 5: Conclusion**
- Both statements are correct. Therefore, the correct option is that both statements are true.

### Final Answer:
Both statements are correct. The correct option is **C**.