Assertion: Work done by friction over a closed path is not zero and no potential energy can be associated with friction.
Reason: Every force encountered in mechanics have an associated potential energy.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true not but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "Work done by friction over a closed path is not zero and no potential energy can be associated with friction."

- When an object moves along a closed path, the work done by friction is indeed not zero. This is because friction opposes the motion of the object, causing energy to be lost in the form of heat and sound. Even though the total displacement is zero (the object returns to its starting point), the work done by friction is negative and accumulates over the path traveled.

### Step 2: Analyze the Reason
The reason states that "Every force encountered in mechanics has an associated potential energy."

- This statement is not entirely accurate. While many forces, such as gravitational and elastic forces, do have associated potential energies, friction does not. Friction is a non-conservative force; it dissipates energy rather than storing it. Therefore, it does not have potential energy associated with it.

### Step 3: Conclusion
From the analysis:
- The assertion is correct: Work done by friction over a closed path is indeed not zero, and no potential energy can be associated with friction.
- The reason is incorrect: Not every force has an associated potential energy, and friction is an example of a force that does not.

### Final Answer
Thus, the assertion is true, and the reason is false. The correct option is that the assertion is true, and the reason is false.

---