When the switching means disconnect the motor from {HEAD ~ the electrical power source}, the disks coast to {TAIL ~ a stop} 
When the switching means disconnect the motor from { HEAD ~ the electrical power source } , the disks coast to { TAIL ~ a stop }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL