випробування на тертя
low-friction polymer
bearing friction test machine
conventional heavy friction clutch
fluid friction
friction bar
friction joint of sight
friction revolution counter
friction spring
friction-wheel drive
friction brake
friction gear
boundary friction
internal friction
surface friction tester
reference friction conditions
surface friction
surface friction drag
force of internal friction in fluid medium
internal friction in fluids
Newtonian law of internal friction
skin friction
skin friction drag
friction
friction damper
with a modicum of friction
gimbal friction
psychological testing
hardware redundancy testing
barrel-testing rod
block testing stand
hydraulic testing equipment
incremental proof testing