STATEMENT-1: Work done by the net force acting on a particle is equal to the change in its kinetic energy.
STATEMENT-2: Change in potential energy is always equal to the work done by external forces.
STATEMENT-3: Work energy theorem is not applicable, if the work is done by the non-conservative forces

Options

A. T T F
B. T F T
C. T F F
D. F T T

Answer

To analyze the statements provided in the question, we will evaluate each statement step by step.

### Step 1: Evaluate Statement 1
**Statement 1:** Work done by the net force acting on a particle is equal to the change in its kinetic energy.

**Solution:**
This statement is a direct application of the Work-Energy Theorem, which states that the work done by the net force on an object is equal to the change in its kinetic energy. Mathematically, this can be expressed as:
\[ W = \Delta KE = KE_{final} - KE_{initial} \]
Since this is a well-established principle in physics, **Statement 1 is true**.

### Step 2: Evaluate Statement 2
**Statement 2:** Change in potential energy is always equal to the work done by external forces.

**Solution:**
This statement is not universally true. The change in potential energy is equal to the work done by conservative forces (like gravity) when moving an object between two points in a conservative field. However, the work done by external forces can include non-conservative forces as well. Therefore, the change in potential energy is not always equal to the work done by external forces. Thus, **Statement 2 is false**.

### Step 3: Evaluate Statement 3
**Statement 3:** Work energy theorem is not applicable if the work is done by non-conservative forces.

**Solution:**
The Work-Energy Theorem applies to all forces, but its interpretation changes when non-conservative forces are involved. When non-conservative forces do work, they can change the total mechanical energy of the system (kinetic + potential). However, the theorem still holds in the sense that the net work done by all forces (conservative and non-conservative) will equal the change in kinetic energy. Therefore, the statement as it stands is misleading. However, if interpreted strictly, it can be considered **true** in the context that the work done by non-conservative forces does not conserve mechanical energy.

### Final Evaluation
- **Statement 1:** True
- **Statement 2:** False
- **Statement 3:** True

### Conclusion
The correct assessment of the statements is:
- Statement 1: True
- Statement 2: False
- Statement 3: True