MMET 401 TEST 1 QUESTIONS WITH
100% CORRECT ANSWERS
What is meant by the term pressure head? - Answer- internal energy of a fluid due to
the pressure exerted on its container
How is the viscosity of a fluid affected by temperature change? - Answer- viscosity
increases
The image on the right shows a pressure booster used in a manufacturing facility to
help apply a clamping force onto a work piece. The inlet are supply is 100 psi, the air
piston diameter is 5.04", the second piston diameter is 1.13" and the piston that is
applying pressure to the clamp has a diameter of 5.64". What is the force that is applied
to the base of the lever? - Answer- P1, d1, d2, d3 are all given
F1 = P1 *A1
F1 = F2
P2 = F2/A2
P2 = P3
F3 = P3 *A3
At a velocity of 3 m/s, how many m3 /s of fluid will flow through a 0.10 m inside diameter
pipe? - Answer- water flowing = cross sectional area * velocity
= pi*d^2/4 *v
How long would it take a 20 gpm pump to extend a 4 in diameter cylinder through a 20
in stroke? - Answer- -find cylinder area
GPM = (A*length/2.31 *time)*60
-solve for time
-60 is for min into sec
A cylinder with a 8cm diameter piston and 3cm diameter rod receives fluid at 30 Lpm. If
the cylinder has a stroke of 35 cm, what is the maximum cycle rate that can be
accomplished? - Answer- find cylinder volume - area and convert to meters
-one rev = 2 strokes
total volume for one rev, V = volume *2
# of revs = Q/V
What are the four primary functions of a hydraulic fluid? - Answer- 1. Transmit power
2. lubricate system
, 3. sealing the clearances
4. dissipate heat
5. contamination control
Name 10 properties that a hydraulic fluid should possess. - Answer- -lubricity
-chemical stability
-ideal viscosity
-low weight density
-foam resistance
-low volatility
-nontoxicity
-fire resistance
-compatibility w/ system
-high degrees of incompressibility
-good heat transfer abilities
specific weight - Answer- weight per unit volume of a material
y = pg
density - Answer- its mass per unit volume
p = m/v
specific gravity - Answer- ratio of mass/weight density of a liquid compared to water
SG = Yl/Yw, Pl/Pw
What is the difference between pressure and force? - Answer- force is the total impact
of one object on another, whereas pressure is the physical quantity of force spread over
a certain area
Name 2 undesirable results when using an oil that has viscosity that is too High? -
Answer- high resistance to flow and increased pressure drops due to inc resistance to
flow
Name 2 undesirable results when using an oil that has viscosity that is too Low? -
Answer- increased internal leakage, excess wear
A hydraulic fluid has a specific weight of 55 lb/ft3. What is its specific gravity? What is its
density? - Answer- Yf = 55, Yw = 62.43 lb/ft3
SG = 55/62.43
Pl = Pw * SG
Air at 20°C and atmospheric pressure has a density of 1.23lb/ ft3 . a. Find its specific
gravity. b. What is the ratio of specific gravity of water divided by the specific gravity of
air at 20°C and atmospheric pressure?
c. What is the significance of ratio in part b? - Answer- SG = Pl/Pw
100% CORRECT ANSWERS
What is meant by the term pressure head? - Answer- internal energy of a fluid due to
the pressure exerted on its container
How is the viscosity of a fluid affected by temperature change? - Answer- viscosity
increases
The image on the right shows a pressure booster used in a manufacturing facility to
help apply a clamping force onto a work piece. The inlet are supply is 100 psi, the air
piston diameter is 5.04", the second piston diameter is 1.13" and the piston that is
applying pressure to the clamp has a diameter of 5.64". What is the force that is applied
to the base of the lever? - Answer- P1, d1, d2, d3 are all given
F1 = P1 *A1
F1 = F2
P2 = F2/A2
P2 = P3
F3 = P3 *A3
At a velocity of 3 m/s, how many m3 /s of fluid will flow through a 0.10 m inside diameter
pipe? - Answer- water flowing = cross sectional area * velocity
= pi*d^2/4 *v
How long would it take a 20 gpm pump to extend a 4 in diameter cylinder through a 20
in stroke? - Answer- -find cylinder area
GPM = (A*length/2.31 *time)*60
-solve for time
-60 is for min into sec
A cylinder with a 8cm diameter piston and 3cm diameter rod receives fluid at 30 Lpm. If
the cylinder has a stroke of 35 cm, what is the maximum cycle rate that can be
accomplished? - Answer- find cylinder volume - area and convert to meters
-one rev = 2 strokes
total volume for one rev, V = volume *2
# of revs = Q/V
What are the four primary functions of a hydraulic fluid? - Answer- 1. Transmit power
2. lubricate system
, 3. sealing the clearances
4. dissipate heat
5. contamination control
Name 10 properties that a hydraulic fluid should possess. - Answer- -lubricity
-chemical stability
-ideal viscosity
-low weight density
-foam resistance
-low volatility
-nontoxicity
-fire resistance
-compatibility w/ system
-high degrees of incompressibility
-good heat transfer abilities
specific weight - Answer- weight per unit volume of a material
y = pg
density - Answer- its mass per unit volume
p = m/v
specific gravity - Answer- ratio of mass/weight density of a liquid compared to water
SG = Yl/Yw, Pl/Pw
What is the difference between pressure and force? - Answer- force is the total impact
of one object on another, whereas pressure is the physical quantity of force spread over
a certain area
Name 2 undesirable results when using an oil that has viscosity that is too High? -
Answer- high resistance to flow and increased pressure drops due to inc resistance to
flow
Name 2 undesirable results when using an oil that has viscosity that is too Low? -
Answer- increased internal leakage, excess wear
A hydraulic fluid has a specific weight of 55 lb/ft3. What is its specific gravity? What is its
density? - Answer- Yf = 55, Yw = 62.43 lb/ft3
SG = 55/62.43
Pl = Pw * SG
Air at 20°C and atmospheric pressure has a density of 1.23lb/ ft3 . a. Find its specific
gravity. b. What is the ratio of specific gravity of water divided by the specific gravity of
air at 20°C and atmospheric pressure?
c. What is the significance of ratio in part b? - Answer- SG = Pl/Pw
