Statement-1: Pendulum clock stops working on the spaceship
Statement-2: Pendulum of the pendulum clock falls down on the spaceship.

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.

Answer

To analyze the statements provided in the question, we will evaluate each statement based on the principles of physics, particularly in relation to gravity and motion in a spaceship.

### Step-by-Step Solution:

1. **Understanding Statement 1**:
- The first statement claims that a pendulum clock stops working on a spaceship.
- A pendulum clock operates based on the gravitational force acting on the pendulum. The time period of a pendulum is given by the formula:
\[ T = 2\pi \sqrt{\frac{l}{g}} \]
where \( T \) is the time period, \( l \) is the length of the pendulum, and \( g \) is the acceleration due to gravity.

2. **Condition Inside a Spaceship**:
- Inside a spaceship that is in free fall (like in orbit), the astronauts and objects inside experience weightlessness. This means that the effective gravitational force \( g \) acting on them is essentially zero.
- Since \( g \) is zero, the time period \( T \) becomes undefined, and the pendulum does not oscillate. Therefore, the pendulum clock would not function as intended.

3. **Conclusion for Statement 1**:
- Hence, Statement 1 is **true**: A pendulum clock stops working on a spaceship due to the lack of effective gravity.

4. **Understanding Statement 2**:
- The second statement claims that the pendulum of the pendulum clock falls down on the spaceship.
- In a weightless environment, objects do not fall in the traditional sense. Instead, they float alongside the astronauts and the clock.
- Therefore, the pendulum does not fall down; it remains in a state of free fall with the spaceship.

5. **Conclusion for Statement 2**:
- Thus, Statement 2 is **false**: The pendulum does not fall down on the spaceship; it experiences weightlessness just like everything else inside.

6. **Final Evaluation**:
- Based on the evaluations, we conclude:
- Statement 1 is true.
- Statement 2 is false.
- Therefore, the correct answer to the question is option C: Statement 1 is true, Statement 2 is false.