MET230: Hydraulics and Pneumatics Mid-Term Exam

MET230: Hydraulics and Pneumatics
Mid-Term Exam

Question 1
Which of the following is NOT true about fluid power?
A. A fluid power system uses either a liquid or a gas to generate, control, and
transmit power
B. Fluid power is another term for fluid transport
C. Hydraulics uses liquids whereas pneumatics uses gases
D. Power capacity of fluid systems is limited only by the physical strength of the
material used for each component
E. None of the above
Question 2
Which of the following statements is true about dynamic pumps?
A. Dynamic pumps are used for low-volume, high pressure applications
B. The flow rate output of dynamic pumps decreases as the circuit resistance
decreases
C. Centrifugal and axial pumps are all classified as dynamic pumps
D. Dynamic pumps are self-priming
E. None of the above
Question 3
Which of the following statements is NOT true about limited rotation hydraulic
motors?
A. They are classified as rotary actuators
B. They are also called oscillating motors
C. They rotate through less than one complete cycle
D. They can rotate only in clockwise direction
E. None of the above
Question 4
Which of the following statements is true about different efficiencies of a hydraulic
motor?
A. The definition of the volumetric efficiency of a hydraulic motor is the same as
that of a pump.
B. The definition of the mechanical efficiency of a hydraulic motor is the same
as that of a pump.
C. The overall efficiency of a hydraulic motor is, as in the case of pumps, equals
to the product of the volumetric and mechanical efficiencies
D. Volumetric, mechanical, and overall efficiency of a motor are always greater
the volumetric, mechanical, and overall efficiency of a pump respectively
E. None of the above

Question 6
Which of the following is NOT true about hydraulic motors?
A. A hydraulic motor delivers more torque than it theoretically should
B. A motor uses more flow than it theoretically should
C. In vane motors, vanes are held in contact with cam ring by springs or by
being pressure-loaded
D. Hydraulic motors extract energy from a fluid and convert it to mechanical
energy
E. All of the above
Question 7
Which of the following symbols represent a pilot check valve?
A.
B.
C.
D.
E. None of the above
Solution
B
Question 8
Which of the following symbols represent a single acting cylinder?
A.
B.
C.
D.
E. None of the above
SOLUTION
A.
Question 9
Which of the following is the purpose of a regenerative circuit?
A. To regenerate the viscosity of the working fluid
B. To remove extra moisture from the working fluid
C. To slowdown the extending speed of a double-acting cylinder

D. To control the temperature of the working fluid
E. None of the above
Question 10
Which of the following is the purpose of fail-safe circuits?
A. Fail-safe circuits are designed to provide overload protection for system
components
B. Fail-safe circuits are designed to regulate the flow rate of the working fluid
C. Fail-safe circuits are designed to control the bulk modulus of the working fluid
D. A, B, and C
E. None of the above
Part 2. (50/100)
(Open book only)
Problem 1
A hydraulic fluid has a specific weight of 57 lb/ft3. What is its specific gravity SG?
What is its density ρ? (
Note: the specific weight of water is γwater = 62.4 lb/ft3, and
the acceleration of gravity g = 32.2 ft/s2)