USPS 955 exam with questions and correct answers
with solutions 2025
Which one of the following CANNOT be used as self-lubricating bushings? - CORRECT
ANSWER-Sleeved bushings consist of metal, plastic, or reinforced fibers composites
sleeves that reduce noise and vibrations by reducing the friction between moving
mechanical parts.
Oil (lubricants) foaming in gear mechanism is caused by: - CORRECT ANSWER-
Contamination of lubricants with water
Which are the three main factors to consider when choosing a lubricant? - CORRECT
ANSWER-Temperature, workload, speed of moving parts
The benefit/benefits of dynamic balancing are: - CORRECT ANSWER-Low vibrations,
low noise, and higher bearing life
____________ roller bearings are available in cylindrical, barrel and taper shaped
rollers. - CORRECT ANSWER-staggered
When pressing a bearing into the housing, you should press against _________. -
CORRECT ANSWER-the outer race only
The purpose of a cylindrical roller bearing is to _________. - CORRECT ANSWER-
Contain redial motion of the shaft
The three basic shapes of roller bearings are: - CORRECT ANSWER-cylindrical, barrel,
and tapered
The purpose of a thrust bearing is to: - CORRECT ANSWER-Contain axial motion of
the shaft
_____________ cause overheating in the bearing and reduces the bearing life. -
CORRECT ANSWER-insufficient lubrication and speed
In order to remove a bearing from a steel shaft, ___________ can be used without
damaging the bearing or the shaft. - CORRECT ANSWER-Dry ice and liquid nitrogen
____________ load is acting on the plane of the bearings' axis of rotation. - CORRECT
ANSWER-Axial
Which of the following statements is true? - CORRECT ANSWER-Zero-film are sliding
bearing which are lubrication-free
The characteristic number of the bearing is given by:
,Z=absolute viscosity of the lubricant, N= speed of journal, p=bearing pressure -
CORRECT ANSWER-ZN/p
Also called eccentrically loaded bearing is: - CORRECT ANSWER-Offset bearing
Reducing noise from sprockets and chain can be done by: - CORRECT ANSWER-
Choosing sprockets with more teeth, using a lighter chain, lubricating the bottom of the
sprocket tooth
What is the advantage of bushing? - CORRECT ANSWER-Self-lubricating, less noise,
less vibration
Which of the following lubrication system is used in two stroke engines? - CORRECT
ANSWER-Mist system
Thrust ball bearing are used to __________. - CORRECT ANSWER-Counteract axial
force
Which one of the following CANNOT be used as self-lubricating bushings? - CORRECT
ANSWER-Sleeved bushings consist of metal, plastic, or reinforced fibers composites
sleeves that reduce noise and vibrations by reducing the friction between moving
mechanical parts.
The throwout bearing and the spring diaphragm in a clutch are connected: - CORRECT
ANSWER-When the clutch pedal is pressed
Bearing failure in motors can be caused due to wrong selection of bearings. A motor
mounted horizontally or vertically needs _____________ types of bearings. -
CORRECT ANSWER-different
For a journal bearing design, the clearance ratio ("clearance") should be approximately
considered as: - CORRECT ANSWER-0.0010
Select a bearing to sustain axial as well as radial loads: - CORRECT ANSWER-
Tapered roller bearing
Which of the following can provide bi-directional thrust load? - CORRECT ANSWER-
Thrust ball bearings
Hydrostatic bearing usually use __________ as lubricant. - CORRECT ANSWER-Oil
Oil whirl in journal bearing can be prevented by ________ - CORRECT ANSWER-
Providing an obstacle to the whirling fluid or providing the stabilized loading are used to
avoid whirls
, Which of the following wear type occurs the least in a bearing when used in a turbine? -
CORRECT ANSWER-Corrosion
V-belts are superior to flat belts because ________. - CORRECT ANSWER-The belt
does not slip away and slip off from the pulley
A v-belt drive has just had its belts replaced. What must be checked/done as a first
precaution before running the drive? - CORRECT ANSWER-The belts are placed over
the sheaves and in the grooves without forcing
Which one is NOT true for under tension belts: - CORRECT ANSWER-Reduce bearing
and belt life
Which of the following is NOT a procedure for surface and edge wear inspection of a
belt? - CORRECT ANSWER-Confirm that belt can be moved laterally of the drive/idle
shaft
Considering the power transmission through V-belt, which one is not correct?
V-belts are
used at the high-speed end.
used at the low-speed end.
of standard lengths.
of standardized angles. - CORRECT ANSWER-2
The cause of creep in belts is due to: - CORRECT ANSWER-Unequal tension in tight
and slack side of the belt
The inner diameter (ID) and the outer diameter (OD) of a clutch plate pair are 100 mm
and 200 mm respectively. The operating force of the clutch is 23.6 kN. Calculate the
permissible intensity of pressure (N/mm2). - CORRECT ANSWER-1.5
In a two-sprocket chain mechanism, to achieve 150 rpm at the smaller sprocket when
the bigger sprocket (50 teeth) rotates at 50 rpm, what should be the number of teeth of
the smaller sprocket? - CORRECT ANSWER-16
The X gear has 5 teeth and is connected to the motor. The Y gear has 20 teeth and is
an intermediate idler gear. The Z gear has 30 teeth and is connected to the roller. If the
roller's required speed is 50 rpm, what should be the motor's rotating speed? -
CORRECT ANSWER-300
Gear A has 30 teeth and rotates at 30 rpm. Gear B has 15 teeth. How many rpm will
gear B rotate when driven by the same driving gear? - CORRECT ANSWER-60
with solutions 2025
Which one of the following CANNOT be used as self-lubricating bushings? - CORRECT
ANSWER-Sleeved bushings consist of metal, plastic, or reinforced fibers composites
sleeves that reduce noise and vibrations by reducing the friction between moving
mechanical parts.
Oil (lubricants) foaming in gear mechanism is caused by: - CORRECT ANSWER-
Contamination of lubricants with water
Which are the three main factors to consider when choosing a lubricant? - CORRECT
ANSWER-Temperature, workload, speed of moving parts
The benefit/benefits of dynamic balancing are: - CORRECT ANSWER-Low vibrations,
low noise, and higher bearing life
____________ roller bearings are available in cylindrical, barrel and taper shaped
rollers. - CORRECT ANSWER-staggered
When pressing a bearing into the housing, you should press against _________. -
CORRECT ANSWER-the outer race only
The purpose of a cylindrical roller bearing is to _________. - CORRECT ANSWER-
Contain redial motion of the shaft
The three basic shapes of roller bearings are: - CORRECT ANSWER-cylindrical, barrel,
and tapered
The purpose of a thrust bearing is to: - CORRECT ANSWER-Contain axial motion of
the shaft
_____________ cause overheating in the bearing and reduces the bearing life. -
CORRECT ANSWER-insufficient lubrication and speed
In order to remove a bearing from a steel shaft, ___________ can be used without
damaging the bearing or the shaft. - CORRECT ANSWER-Dry ice and liquid nitrogen
____________ load is acting on the plane of the bearings' axis of rotation. - CORRECT
ANSWER-Axial
Which of the following statements is true? - CORRECT ANSWER-Zero-film are sliding
bearing which are lubrication-free
The characteristic number of the bearing is given by:
,Z=absolute viscosity of the lubricant, N= speed of journal, p=bearing pressure -
CORRECT ANSWER-ZN/p
Also called eccentrically loaded bearing is: - CORRECT ANSWER-Offset bearing
Reducing noise from sprockets and chain can be done by: - CORRECT ANSWER-
Choosing sprockets with more teeth, using a lighter chain, lubricating the bottom of the
sprocket tooth
What is the advantage of bushing? - CORRECT ANSWER-Self-lubricating, less noise,
less vibration
Which of the following lubrication system is used in two stroke engines? - CORRECT
ANSWER-Mist system
Thrust ball bearing are used to __________. - CORRECT ANSWER-Counteract axial
force
Which one of the following CANNOT be used as self-lubricating bushings? - CORRECT
ANSWER-Sleeved bushings consist of metal, plastic, or reinforced fibers composites
sleeves that reduce noise and vibrations by reducing the friction between moving
mechanical parts.
The throwout bearing and the spring diaphragm in a clutch are connected: - CORRECT
ANSWER-When the clutch pedal is pressed
Bearing failure in motors can be caused due to wrong selection of bearings. A motor
mounted horizontally or vertically needs _____________ types of bearings. -
CORRECT ANSWER-different
For a journal bearing design, the clearance ratio ("clearance") should be approximately
considered as: - CORRECT ANSWER-0.0010
Select a bearing to sustain axial as well as radial loads: - CORRECT ANSWER-
Tapered roller bearing
Which of the following can provide bi-directional thrust load? - CORRECT ANSWER-
Thrust ball bearings
Hydrostatic bearing usually use __________ as lubricant. - CORRECT ANSWER-Oil
Oil whirl in journal bearing can be prevented by ________ - CORRECT ANSWER-
Providing an obstacle to the whirling fluid or providing the stabilized loading are used to
avoid whirls
, Which of the following wear type occurs the least in a bearing when used in a turbine? -
CORRECT ANSWER-Corrosion
V-belts are superior to flat belts because ________. - CORRECT ANSWER-The belt
does not slip away and slip off from the pulley
A v-belt drive has just had its belts replaced. What must be checked/done as a first
precaution before running the drive? - CORRECT ANSWER-The belts are placed over
the sheaves and in the grooves without forcing
Which one is NOT true for under tension belts: - CORRECT ANSWER-Reduce bearing
and belt life
Which of the following is NOT a procedure for surface and edge wear inspection of a
belt? - CORRECT ANSWER-Confirm that belt can be moved laterally of the drive/idle
shaft
Considering the power transmission through V-belt, which one is not correct?
V-belts are
used at the high-speed end.
used at the low-speed end.
of standard lengths.
of standardized angles. - CORRECT ANSWER-2
The cause of creep in belts is due to: - CORRECT ANSWER-Unequal tension in tight
and slack side of the belt
The inner diameter (ID) and the outer diameter (OD) of a clutch plate pair are 100 mm
and 200 mm respectively. The operating force of the clutch is 23.6 kN. Calculate the
permissible intensity of pressure (N/mm2). - CORRECT ANSWER-1.5
In a two-sprocket chain mechanism, to achieve 150 rpm at the smaller sprocket when
the bigger sprocket (50 teeth) rotates at 50 rpm, what should be the number of teeth of
the smaller sprocket? - CORRECT ANSWER-16
The X gear has 5 teeth and is connected to the motor. The Y gear has 20 teeth and is
an intermediate idler gear. The Z gear has 30 teeth and is connected to the roller. If the
roller's required speed is 50 rpm, what should be the motor's rotating speed? -
CORRECT ANSWER-300
Gear A has 30 teeth and rotates at 30 rpm. Gear B has 15 teeth. How many rpm will
gear B rotate when driven by the same driving gear? - CORRECT ANSWER-60
