The force of attraction between two unit point masses separted by a unit distance is called

Options

A. gravitational potential
B. acceleration due to gravity
C. gravitational field
D. universal gravitational constant

Explanation

To solve the question, "The force of attraction between two unit point masses separated by a unit distance is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept**:
- The question refers to the gravitational force between two masses. According to Newton's law of gravitation, the force of attraction (F) between two point masses (m1 and m2) is given by the formula:
\[ F = \frac{G \cdot m_1 \cdot m_2}{r^2} \]
where:
- \( G \) is the universal gravitational constant,
- \( m_1 \) and \( m_2 \) are the masses, and
- \( r \) is the distance between the centers of the two masses.

2. **Substituting the Values**:
- In this case, we are dealing with unit point masses, which means \( m_1 = 1 \, \text{kg} \) and \( m_2 = 1 \, \text{kg} \).
- The distance \( r \) is also a unit distance, which means \( r = 1 \, \text{m} \).

3. **Plugging in the Values**:
- Now we substitute these values into the gravitational force formula:
\[ F = \frac{G \cdot 1 \cdot 1}{1^2} \]
- This simplifies to:
\[ F = G \]

4. **Conclusion**:
- The force of attraction between two unit point masses separated by a unit distance is equal to the universal gravitational constant \( G \).
- Therefore, the answer to the question is: **Universal Gravitational Constant**.