If a body is moving with constant speed, then its acceleration

Options

A. Must be zero
B. May be variable
C. May be uniform
D. Both (2) & (3)

Answer

To solve the question "If a body is moving with constant speed, then its acceleration," we need to analyze the relationship between speed, velocity, and acceleration.

### Step-by-Step Solution:

1. **Understanding Speed and Velocity**:
- Speed is a scalar quantity that refers to how fast an object is moving, regardless of its direction.
- Velocity is a vector quantity that includes both speed and direction.

2. **Definition of Acceleration**:
- Acceleration is defined as the rate of change of velocity with respect to time. Mathematically, it can be expressed as:
\[ a = \frac{\Delta v}{\Delta t} \]
where \( a \) is acceleration, \( \Delta v \) is the change in velocity, and \( \Delta t \) is the change in time.

3. **Constant Speed Implication**:
- If a body is moving with constant speed, it means that the speed does not change over time. This implies that the magnitude of the velocity remains constant.

4. **Analyzing Acceleration**:
- For acceleration to be zero, there must be no change in velocity. Since speed is constant, the velocity does not change in magnitude.
- Therefore, if the speed is constant, the change in velocity (\( \Delta v \)) is zero.

5. **Conclusion**:
- Since the change in velocity is zero, the acceleration must also be zero. Thus, we conclude that:
\[ \text{Acceleration} = 0 \]

### Final Answer:
- The correct option is **1. must be 0**.