Which of the following quantities remains constant during uniform circular motion ?

Options

A. Centripetal acceleration
B. Velocity
C. Momentum
D. Speed

Answer

To determine which quantity remains constant during uniform circular motion, let's analyze the situation step by step.

### Step-by-Step Solution:

1. **Understanding Uniform Circular Motion**:
- In uniform circular motion, an object moves in a circular path with a constant speed. However, the direction of the velocity vector changes continuously.

2. **Identifying Key Quantities**:
- The key quantities to consider in this scenario are:
- Speed
- Velocity
- Acceleration
- Momentum

3. **Analyzing Speed**:
- Speed is defined as the magnitude of velocity. In uniform circular motion, the speed remains constant because the object covers equal distances in equal intervals of time.

4. **Analyzing Velocity**:
- Velocity is a vector quantity that includes both magnitude and direction. Although the speed is constant, the direction of the velocity vector changes continuously as the object moves around the circle. Therefore, the velocity is not constant.

5. **Analyzing Acceleration**:
- In uniform circular motion, the object experiences centripetal acceleration directed towards the center of the circle. While the magnitude of this acceleration remains constant, its direction changes as the object moves around the circle. Thus, acceleration is not constant.

6. **Analyzing Momentum**:
- Momentum is defined as the product of mass and velocity (p = mv). Since the velocity is not constant (due to changing direction), the momentum also changes. Therefore, momentum is not constant.

7. **Conclusion**:
- The only quantity that remains constant during uniform circular motion is **speed**.

### Final Answer:
The quantity that remains constant during uniform circular motion is **speed**.

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