A rock is brought from the surface of the moon,

Options

A. its mass will change
B. its weight will change but not mass
C. both mass and weight will change
D. its mass and weight both will remain same .

Answer

To solve the problem regarding the rock brought from the surface of the moon to the earth, we will analyze the concepts of mass and weight.

### Step-by-Step Solution:

1. **Understanding Mass and Weight**:
- **Mass** is a measure of the amount of matter in an object and is constant regardless of location. It is measured in kilograms (kg).
- **Weight** is the force exerted by gravity on an object and is dependent on both the mass of the object and the acceleration due to gravity (g). Weight is calculated using the formula:
\[ \text{Weight} = \text{Mass} \times g \]

2. **Mass of the Rock**:
- When the rock is on the moon, its mass is denoted as \( m \).
- When the rock is brought to the earth, its mass remains the same, \( m \). This is because mass does not change with location.

3. **Weight of the Rock on the Moon**:
- The acceleration due to gravity on the moon is approximately \( g_m \), which is about \( \frac{g}{6} \) (where \( g \) is the acceleration due to gravity on earth).
- Therefore, the weight of the rock on the moon can be calculated as:
\[ \text{Weight on Moon} = m \times g_m = m \times \left(\frac{g}{6}\right) \]

4. **Weight of the Rock on Earth**:
- When the rock is brought to the earth, the acceleration due to gravity is \( g \).
- The weight of the rock on earth can be calculated as:
\[ \text{Weight on Earth} = m \times g \]

5. **Comparison of Weight**:
- Since \( g_m < g \), it follows that the weight of the rock on earth will be greater than its weight on the moon.
- Thus, the weight of the rock changes when it is moved from the moon to the earth.

6. **Conclusion**:
- The mass of the rock remains constant regardless of its location.
- The weight of the rock changes due to the difference in gravitational acceleration between the moon and the earth.

### Final Answer:
- The correct option is: **Option 2** - its weight will change, but not mass.