At the bottom of the tank :
P = ρgH
P = (1000 kg/m³)(10 m/s²)(1 m)
P = 10000 N/m²
F = P • A
F = (10000 N/m²)(1 m²)
F = 10000 N
At the side of the tank :
Pav = ½ρgH
Pav = ½(1000 kg/m³)(10 m/s²)(1 m)
Pav = 5000 N/m²
F = P • A
F = (5000 N/m²)(1 m²)
F = 5000 N
Answer:
The question is incomplete. However, I believe, it is asking for the acceleration of the elevator. This is 3.16 m/s².
Explanation:
By Hooke's law, 
F is the force on a spring, k is the spring constant and e is the extension or compression.
From the question,

This is the force on the mass suspended on the spring. Its acceleration, a, is given by



This acceleration is more than the acceleration due to gravity, g = 9.8 m/s². Hence the elevator must be moving up with an acceleration of
12.96 - 9.8 m/s² = 3.16 m/s²
Answer:
It is because it is a unit of Power(which is a derived quantity)
It would mostly be on their website.