Answer:
1.122 m/s
Explanation:
So usually a river with a speed of 1 meters per second can transport particle that weighs:

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

Previous results tell us the speed (v) is given in terms of the coefficient of friction (k) and the radius of the curve (r) as
v = √(kgr)
v = √(0.20·9.8 m/s²·50 m)
= 7√2 m/s ≈ 9.90 m/s
Clock wise idk i think you should double check my answer