Mechanical waves are

Options

A. A. longitudinal only
B. B. transverse only
C. C. can be both longitudinal or transverse
D. D. require no medium for propagation

Answer

To solve the question "Mechanical waves are," we will analyze the options provided and determine the correct answer based on our understanding of mechanical waves.

### Step-by-Step Solution:

1. **Understanding Mechanical Waves**:
- Mechanical waves are defined as waves that require a medium (solid, liquid, or gas) to propagate. They involve the oscillation of particles in the medium through which they travel.

2. **Types of Mechanical Waves**:
- There are three main types of mechanical waves:
- **Longitudinal Waves**: In these waves, the particle displacement is parallel to the direction of wave propagation. An example is sound waves.
- **Transverse Waves**: In these waves, the particle displacement is perpendicular to the direction of wave propagation. An example is waves on a string.
- **Surface Waves**: These waves travel along the surface of a medium, exhibiting characteristics of both longitudinal and transverse waves. An example is ocean waves.

3. **Analyzing the Options**:
- **Option A**: Longitudinal only - This is incorrect as mechanical waves can also be transverse.
- **Option B**: Transverse only - This is incorrect as mechanical waves can also be longitudinal.
- **Option C**: Can be both longitudinal or transverse - This is correct since mechanical waves can indeed be of both types.
- **Option D**: Required no medium for propagation - This is incorrect as mechanical waves require a medium to travel.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option C: Can be both longitudinal or transverse**.

### Final Answer:
**Option C: Can be both longitudinal or transverse.**

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