Statement`-1:` The work done by all forces on a system equals to the change in kinetic energy of that system . This statement is true even if nonconservative forces act on the system.
Statement `-2:` The total work done by internal forces may be positive.

Options

A. Statement `-1` is True, Statement `-2` is True, Statement`-2` is a correct explanation for Statement`-1`
B. Statement `-1` is True, Statement `-2` is True, Statement`-2` is NOT a correct explanation for Statement`-1`
C. Statement`-1` is True, Statement`-2` is False.
D. Statement`-1` is False,Statement`-2` is True.

Explanation

To analyze the two statements provided, we can break down the reasoning step by step.

### Step 1: Evaluate Statement 1
**Statement 1:** "The work done by all forces on a system equals the change in kinetic energy of that system. This statement is true even if nonconservative forces act on the system."

- According to the work-energy theorem, the total work done on an object is equal to its change in kinetic energy. This holds true regardless of whether the forces acting on the object are conservative (like gravity) or nonconservative (like friction).
- Therefore, Statement 1 is **true**.

### Step 2: Evaluate Statement 2
**Statement 2:** "The total work done by internal forces may be positive."

- Internal forces are forces that the objects within a system exert on each other. The work done by internal forces can indeed be positive, negative, or zero, depending on the nature of the forces and the displacement of the objects involved.
- For example, if two objects within a system are pulling apart, the work done by their internal forces is positive. Conversely, if they are pushing against each other, the work done could be negative.
- Therefore, Statement 2 is also **true**.

### Step 3: Determine the Relationship Between the Statements
- Now we need to determine if Statement 2 provides a correct explanation for Statement 1.
- Statement 1 is based on the work-energy theorem, which applies to all forces acting on a system, while Statement 2 discusses the nature of internal forces specifically.
- The work-energy theorem does not depend on the positivity of internal work; it is a broader principle that applies to all forces, not just internal ones.

### Conclusion
- Both Statement 1 and Statement 2 are **true**.
- However, Statement 2 is **not the correct explanation** for Statement 1.

### Final Answer
- Statement 1 is true, Statement 2 is true, but Statement 2 is not the correct explanation of Statement 1.

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