Updated onderzoek-voorbeeld.md & motion-tracking-system-analysis.md

docs/documentation/research-questions/motion-tracking-system-analysis.md

@@ -12,7 +12,7 @@ and where they've placed the tracking devices.
 
 A path can look like the following
 
-<img height="128" src="../assets/motion-path-example-vertices.png" width="128"/>
+<img height="128" src="../assets/motion-path-example-vertices.png" width="128" alt="Path Point Example"/>
 
 To be able to measure the position of our tracking device, we'll have to use sensors that allow us
 to retrieve useful information that can provide us with either position or velocity. The device will have
@@ -45,4 +45,6 @@ Second, to convert our relative acceleration rotation to a useful position, we'l
 acceleration vector `A(x, y, z)` and rotation vector `R(x, y, z)` to an acceleration vector that is
 perpendicular to the normal vector of the earth. This is because the acceleration vector of the device
 is relative to its own axes, and not to the earth's normal vector.
-To convert this, we'll have to multiply the acceleration vector `A(x, y, z)` by the rotation matrix
+To convert this, we'll have to multiply the acceleration vector `A(x, y, z)` by the rotation matrix
+with negative angles, to rotate it back  to be perpendicular with the normal of the earth.
+After