There are no necessary conditions there’s always waves the ocean is never still or if your talking about a lake you need movement
Answer:
10 meters per seconds or 10m/s
Explanation:
The chair does not move along the vertical direction: this means that the net force on the vertical direction is zero.
There are three forces acting along the vertical direction:
- The weight, acting downward: 
- The component of the force F perpendicular to the floor, acting downward: 
- The normal force N, acting upwards.
Since the net force must be zero, we have:

From which we can find the value of N:

A solution is a homogeneous mixture such as salt water