The body diagram on my clipboard came into focus, and I realized Danny was speaking to me.
Note that figure 1 and 2 are not yet free body diagrams.
The analysis begins with the free body diagram in the co-rotating frame where the water appears stationary.
A simple free body diagram, shown above, of a block on a ramp illustrates this.
The first drawing is the situation of the element or what most people call a free body diagram.
This is done using a free body diagram.
I would not need photographs or body diagrams.
The free body diagram on the right is for a projectile that experiences air resistance and the effects of gravity.
It is analogous to the classical mechanics concept of the free body diagram.