a force measurement device for obtaining a measurement indicative of {HEAD ~ the frictional force} resisting {TAIL ~ movement} of the sample as it is moved in said first direction 
resisting
a force measurement device for obtaining a measurement indicative of { HEAD ~ the frictional force } resisting { TAIL ~ movement } of the sample as it is moved in said first direction
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH