The process 6, wherein {HEAD ~ the angle} of {TAIL ~ movement} about the pivot is about 60° 
of
The process 6 , wherein { HEAD ~ the angle } of { TAIL ~ movement } about the pivot is about 60 °
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH