My inference is that the water molecules are moving up and down. I don't know for sure but i'm usually correct.
Ok so we know:
The time (t) is 18seconds
The acceleration (a) is 2.2m/s2
The displacement (r) is 660
Using the equation

With 'u' being the initial velocity we want, we get:

So:

So:

So the original/initial velocity was 16.8666 or 16.87 m/s
Hope this helped
Complete Question
At what angle should the axes of two Polaroids be placed so as to reduce the intensity of the incident unpolarized light to 1/5.
Answer:
The angle is
Explanation:
From the question we are told that
The light emerging from second Polaroid is 1/5 the unpolarized
Generally the intensity of light emerging from the first Polaroid is mathematically represented as

Generally from the Malus law the intensity of light emerging from the second Polaroid is mathematically represented

=> 
=> 
From the question


=> ![\theta = cos ^{-1} [\sqrt{\frac{2}{5}} ]](https://tex.z-dn.net/?f=%5Ctheta%20%3D%20%20%20cos%20%5E%7B-1%7D%20%5B%5Csqrt%7B%5Cfrac%7B2%7D%7B5%7D%7D%20%20%5D)
=> 
Answer:
The total work that the rope does to Mangnus is - 5780 Jules.
Explanation:
By definition, the work is defined as:
Where F and d are the force and the total displacement. Note that in the definition the product is a scalar product since F and d are both vectors.
Take into account that according to third Newton's law the force that the rope does to Magnus is opposite to the force that Magnus does to the rope, therefore the scalar product will be negative due the rope's force goes against to Magnus displacement.
For calculating the work, we take 2500 N as the value for the force and 2.312 meters as the value for the displacement:

From Greek meaning not divisible.