Many great rivers flow towards the equator, what effect does the sediment they carry to sea have on the rotation of the earth?

Options

A. The rotation of the earth slows down
B. The rotation of theearth speeds up
C. No effect un the rotation of the earth
D. None

Answer

To solve the question regarding the effect of sediment carried by rivers flowing towards the equator on the rotation of the Earth, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the System**:
- The Earth rotates around its axis, which is an imaginary line passing through the North and South Poles. The rotation is characterized by its angular velocity (ω).

2. **Identifying the Flow of Rivers**:
- Many great rivers flow towards the equator, carrying sediments along with them. As these rivers deposit sediments at the equator, there is a significant accumulation of material in this region.

3. **Effect of Sediment Accumulation**:
- When sediments accumulate near the equator, they effectively change the distribution of mass on the Earth. This redistribution of mass affects the moment of inertia (I) of the Earth.

4. **Understanding Moment of Inertia**:
- The moment of inertia is a measure of an object's resistance to changes in its rotation. For a rotating body, if the mass is distributed further from the axis of rotation, the moment of inertia increases.

5. **Increase in Moment of Inertia**:
- As sediments accumulate at the equator, the moment of inertia of the Earth increases. This is because more mass is located farther from the axis of rotation.

6. **Conservation of Angular Momentum**:
- According to the principle of conservation of angular momentum, if the moment of inertia increases, the angular velocity (ω) must decrease to keep the angular momentum (L = Iω) constant.

7. **Conclusion**:
- Therefore, as the moment of inertia increases due to the accumulation of sediments, the angular velocity of the Earth decreases. This means that the rotation of the Earth slows down, resulting in longer periods for the Earth to complete one rotation.

### Final Answer:
The accumulation of sediments carried by rivers flowing towards the equator increases the moment of inertia of the Earth, which in turn decreases its angular velocity, causing the rotation of the Earth to slow down.

---