The friction resistance force adds to {TAIL ~ the torsional resistance force} of the spring during {HEAD ~ application} of the pedal and subtracts from the torsional resistance force of the spring upon release of the pedal, whereby to create a hysteresis effect 
The friction resistance force adds to { TAIL ~ the torsional resistance force } of the spring during { HEAD ~ application } of the pedal and subtracts from the torsional resistance force of the spring upon release of the pedal , whereby to create a hysteresis effect
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH