Choose the correct statement:

Options

A. The magnitudes of speed and velocity are same when a body travels in a straight line path.
B. Average speed of a moving body can be equal to zero, but its average velocity cannot be equal to zero.
C. To describe the velocity, direction is necessary.
D. Both (a) and ( c)

Answer

To solve the question, we need to analyze the statements provided and determine which one is correct based on our understanding of speed, velocity, and their definitions.

### Step-by-Step Solution:

1. **Understanding Speed and Velocity**:
- Speed is defined as the distance traveled divided by the time taken. It is a scalar quantity, which means it only has magnitude.
- Velocity is defined as the displacement divided by the time taken. It is a vector quantity, which means it has both magnitude and direction.

2. **Analyzing the First Statement**:
- The first statement claims: "The magnitudes of speed and velocity are the same when a body travels in a straight line path."
- When an object moves in a straight line, the distance traveled is equal to the displacement. Therefore, in this case, the speed (distance/time) and velocity (displacement/time) will have the same magnitude. This statement is **correct**.

3. **Analyzing the Second Statement**:
- The second statement claims: "Average speed of a moving body can be equal to zero."
- Average speed is calculated as total distance traveled divided by total time taken. If a body is moving, it must cover some distance, which means the average speed cannot be zero. This statement is **incorrect**.

4. **Analyzing the Third Statement**:
- The third statement claims: "To describe the velocity, direction is necessary."
- Since velocity is a vector quantity, it is essential to specify both magnitude and direction to describe it accurately. This statement is **correct**.

5. **Conclusion**:
- The correct statements are the first and the third. Therefore, the answer to the question is that both statements A (the first statement) and C (the third statement) are correct.

### Final Answer:
The correct statements are:
- The magnitudes of speed and velocity are the same when a body travels in a straight line path. (Correct)
- To describe the velocity, direction is necessary. (Correct)

Thus, the answer is option number 4, which states that both A and C are correct.

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