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 concepts of speed, velocity, and acceleration.

### Step-by-Step Solution:

1. **Understanding Constant Speed**:
- When a body is moving with constant speed, it means that the magnitude of its velocity does not change. For example, if a car is moving at a speed of 60 km/h, it continues to move at that speed.

**Hint**: Remember that speed is a scalar quantity, which only considers magnitude.

2. **Velocity and Direction**:
- Velocity is a vector quantity, which means it has both magnitude and direction. If the direction of the body’s motion changes, then the velocity changes even if the speed remains constant.

**Hint**: Consider how direction affects velocity even if speed is unchanged.

3. **Acceleration Definition**:
- Acceleration is defined as the rate of change of velocity with respect to time. If either the magnitude or direction of velocity changes, the body is said to be accelerating.

**Hint**: Recall the formula for acceleration: \( a = \frac{\Delta v}{\Delta t} \).

4. **Example of Uniform Circular Motion**:
- A classic example is uniform circular motion, where an object moves in a circle at a constant speed. Although the speed is constant, the direction of the object is continuously changing, which means the velocity is changing.

**Hint**: Think about how even at constant speed, changing direction results in acceleration.

5. **Conclusion on Acceleration**:
- Therefore, if a body is moving with constant speed, its acceleration can be non-zero if the direction of motion is changing. It can be constant or variable depending on the nature of the motion.

**Hint**: Consider scenarios where speed is constant but direction changes, leading to acceleration.

### Final Answer:
If a body is moving with constant speed, its acceleration can be non-zero if the direction is changing. Thus, it can be variable or uniform depending on the motion.