A: When a satellite is orbiting then no energy is required to keep moving n its orbit .
R : The total mechanical energy of a satellite is conserved .

Options

A. If both Assertion & Reason are true . And the reason is the correct explanation of the assertion , then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2)
C. If Assertion is true statement but Reason is false , then mark (3)
D. It will move the same speed , tangentially to the spacecraft

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the statement.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that when a satellite is orbiting, no energy is required to keep moving in its orbit. This is true because, in a stable orbit, the gravitational force provides the necessary centripetal force to keep the satellite in motion. There is no need for additional energy input to maintain this motion.

**Hint**: Consider how gravitational forces work in maintaining the orbit of a satellite.

2. **Understanding the Reason (R)**:
- The reason states that the total mechanical energy of a satellite is conserved. In orbital motion, the total mechanical energy (which is the sum of kinetic energy and potential energy) remains constant. This is because, as the satellite moves in its orbit, its potential energy decreases while its kinetic energy increases, and vice versa, but the total remains constant.

**Hint**: Recall the relationship between kinetic energy, potential energy, and total mechanical energy in a gravitational field.

3. **Analyzing the Relationship**:
- Since both the assertion and the reason are true, we need to determine if the reason correctly explains the assertion. The reason does explain why no energy is required to maintain the satellite's motion: the conservation of mechanical energy means that the satellite can continue to orbit without any additional energy input.

**Hint**: Think about how conservation laws apply in physics and how they relate to motion in a gravitational field.

4. **Conclusion**:
- Both the assertion (A) and the reason (R) are true, and the reason provides a correct explanation for the assertion. Therefore, the correct option is that both statements are true and the reason is the correct explanation for the assertion.

### Final Answer:
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

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