If the static friction between two surface P and Q is measured to be 50 N, then the sliding friction between these two surface is most likely to be :

Options

A. 75 N
B. 45 N
C. 55 N
D. 65 N

Answer

To solve the problem, we need to understand the relationship between static friction and sliding (kinetic) friction. Here’s the step-by-step solution:

### Step 1: Understand the Definitions
- **Static Friction**: This is the frictional force that prevents two surfaces from sliding past each other. It acts when the surfaces are at rest relative to each other.
- **Sliding (Kinetic) Friction**: This is the frictional force acting between two surfaces that are sliding against each other.

### Step 2: Analyze the Given Information
- We are given that the static friction between surfaces P and Q is measured to be **50 N**.

### Step 3: Apply the Relationship Between Static and Sliding Friction
- It is a known fact that the maximum static friction is always greater than the sliding friction. Therefore, if the static friction is 50 N, the sliding friction must be less than 50 N.

### Step 4: Evaluate the Options
- We need to find the value of sliding friction from the options provided. The sliding friction must be less than 50 N.
- Let's consider the options:
1. **75 N** - This is greater than 50 N, so it is not possible.
2. **45 N** - This is less than 50 N, so it is a possible value.
3. **55 N** - This is greater than 50 N, so it is not possible.
4. **65 N** - This is also greater than 50 N, so it is not possible.

### Step 5: Conclusion
- The only option that is less than 50 N is **45 N**. Therefore, the sliding friction between surfaces P and Q is most likely to be **45 N**.

### Final Answer
The sliding friction between surfaces P and Q is **45 N**.

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