To solve this problem we will use the concepts related to hydrostatic pressure. Which determines the pressure of a body at a given depth of a liquid.
Mathematically this can be described as
Here
= Density
g = Gravity
h = Height (Depth)
If we replace the values given in the equation we will have to
Therefore the pressure at the bottom will be 9.8kPa
The equation of our ellipse is:
(1)
First, let's reduce the equation of the ellipse to the standard form:
To do that, we should divide both terms of equation (1) by 6400, and we get:
This is a vertical ellipse (because ) centered in the origin, and so the distance of its foci from the origin (on the y axis) is given by
Therefore, the position of the two foci is (0,6) and (0,-6)
Mechanical advantage is defined as
MA = 4
now we will have
as we need to pull up a box of weight 200 N
now by above formula we can find how much force it requires to pull up the box
so it requires 50 N force to pull the weight of 200 N