Answer:
1.122 m/s
Step-by-step explanation:
So usually a river with a speed of 1 meters per second can transport particle that weighs:
![1^6 = 1 kg](https://img.qammunity.org/2020/formulas/physics/high-school/tqar8tv4d0kmssu7jkdkn31xz0eln0nv52.png)
If the particle is twice as massive as usual, then its weights would be 1 * 2 = 2kg
This means the river must be flowing at a speed of
![2^{(1)/(6)} = 1.122 m/s](https://img.qammunity.org/2020/formulas/physics/high-school/kbmkab9duhugdrva60g3cmnbv5g2tj5de8.png)