Answer:1.27
Explanation:
Given
incident angle 
refracted angle 
Suppose
is the refractive index of material then using Snell's law we can write

where
=refractive index of air



True it’s true because in the book it said all that stuff
It is potential energy because the band is not in movement, th band has the potential to move.
Answer:
The Hydrostatic force is 
The location of pressure center is
Explanation:
From the question we are told that
The height of the gate is 
The weight of the gate is 
The height of the water is 
The density of water is 
Note used
for height of water and height of gate immersed by water since both have the same value
The area of the gate immersed in water is mathematically represented as

substituting values


The hydrostatic force is mathematically represented as

Where


So


The center of pressure is mathematically represented as

Where
is the moment of inertia of the gate which mathematically represented as

The
is the height of gate immersed in water
Thus

