Exercise: Shutter Speeds

My camera is set on the tripod, and set to TV, which leaves me to select the shutter speed, and the camera selecting the aperture.
I went through the whole range of shutter speeds for this project, ranging from 1/4000 to 30".
The slowest shutter speed at which the movement is sharply frozen is picture 7, 1/50  f11.

Here are the range of photos to show the results, some of them are under or over exposed.  The shutter speeds and apertures are listed below:
1.  1/ 4000  f4.5
2.  1/2000  f4.5
3.  1/1000  f4.50
4.  1/500  f4.50
5.  1/200  f5.6
6.  1/100  f8.0
7.  1/50  f11
8.  1/20  f18
9.  1/10  f25
10.  0"8  f29
11.  0"3  f29
12.  1"  f29
13.  4"  f29
14.  20"  f29
15.  30" f29