http://www.shutterangle.com/2012/cinematic-look-frame-rate-shutter-speed/

https://www.cinema5d.com/global-vs-rolling-shutter/

https://www.wikihow.com/Choose-a-Camera-Shutter-Speed

https://www.provideocoalition.com/shutter-speed-vs-shutter-angle/

Shutter is the device that controls the amount of light through a lens. Basically in general it controls the amount of time a film is exposed.

Shutter speed is how long this device is open for, which also defines motion blur… the longer it stays open the blurrier the image captured.

The number refers to the amount of light actually allowed through.

As a reference, shooting at 24fps, at 180 shutter angle or 1/48th of shutter speed (0.0208 exposure time) will produce motion blur which is similar to what we perceive at naked eye

Talked of as in (shutter) angles, for historical reasons, as the original exposure mechanism was controlled through a pie shaped mirror in front of the lens.

A shutter of 180 degrees is blocking/allowing light for half circle.  (half blocked, half open). 270 degrees is one quarter pie shaped, which would allow for a higher exposure time (3 quarter pie open, vs one quarter closed) 90 degrees is three quarter pie shaped, which would allow for a lower exposure (one quarter open, three quarters closed)

The shutter angle can be converted back and fort with shutter speed with the following formulas:
https://www.provideocoalition.com/shutter-speed-vs-shutter-angle/

shutter angle =
(360 * fps) * (1/shutter speed)
or
(360 * fps) / shutter speed

shutter speed =
(360 * fps) * (1/shutter angle)
or
(360 * fps) / shutter angle

For example here is a chart from shutter angle to shutter speed at 24 fps:
270 = 1/32
180 = 1/48
172.8 = 1/50
144 = 1/60
90 = 1/96
72 = 1/120
45 = 1/198
22.5 = 1/348
11 = 1/696
8.6 = 1/1000

The above is basically the relation between the way a video camera calculates shutter (fractions of a second) and the way a film camera calculates shutter (in degrees).

Smaller shutter angles show strobing artifacts. As the camera only ever sees at least half of the time (for a typical 180 degree shutter). Due to being obscured by the shutter during that period, it doesn’t capture the scene continuously.

This means that fast moving objects, and especially objects moving across the frame, will exhibit jerky movement. This is called strobing. The defect is also very noticeable during pans.  Smaller shutter angles (shorter exposure) exhibit more pronounced strobing effects.

Larger shutter angles show more motion blur. As the longer exposure captures more motion.

Note that in 3D you want to first sum the total of the shutter open and shutter close values, than compare that to the shutter angle aperture, ie:

shutter open -0.0625
shutter close 0.0625
Total shutter = 0.0625+0.0625 = 0.125
Shutter angle = 360*0.125 = 45

shutter open -0.125
shutter close 0.125
Total shutter = 0.125+0.125 = 0.25
Shutter angle = 360*0.25 = 90

shutter open -0.25
shutter close 0.25
Total shutter = 0.25+0.25 = 0.5
Shutter angle = 360*0.5 = 180

shutter open -0.375
shutter close 0.375
Total shutter = 0.375+0.375 = 0.75
Shutter angle = 360*0.75 = 270

Faster frame rates can resolve both these issues.