Which of the following statements are incorrect?

Options

A. The point at which a planet is closest to the sun is perihelion.
B. The point at which a planet is farthest from the sun is aphelion.
C. The areal velocity of a planet around the sun is not constant.
D. Gravitational force between two bodies can be attractive or repulsive.

Answer

To determine which of the statements provided are incorrect, we will analyze each statement one by one based on our understanding of gravitation and planetary motion.

### Step-by-Step Solution:

1. **Statement 1: The point at which a planet is closest to the sun is perihelion.**
- **Analysis:** This statement is true. In an elliptical orbit, the point where a planet is closest to the Sun is indeed called perihelion.

2. **Statement 2: The point at which a planet is farthest from the sun is aphelion.**
- **Analysis:** This statement is also true. The point where a planet is farthest from the Sun is referred to as aphelion.

3. **Statement 3: The aerial velocity of a planet around the sun is not constant.**
- **Analysis:** This statement is incorrect. According to Kepler's second law, the aerial velocity (the area swept out by the line connecting the planet to the Sun in a given time) is constant. Therefore, this statement is false.

4. **Statement 4: Gravitational force between two bodies can be attractive or repulsive.**
- **Analysis:** This statement is also incorrect. The gravitational force is always attractive; it never acts as a repulsive force. This is a fundamental property of gravity.

### Conclusion:
- The incorrect statements are:
- Statement 3: "The aerial velocity of a planet around the sun is not constant."
- Statement 4: "Gravitational force between two bodies can be attractive or repulsive."

### Final Answer:
The incorrect statements are statements 3 and 4.

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