Theory of Machine Online Practice Test - Set 03 - ObjectiveBooks

# Practice Test: Question Set - 03

1. The frictional torque transmitted in a truncated conical pivot bearing, considering uniform wear, is
(A) (1/2). Î¼ W cosec Î± (r₁ + r₂)
(B) (2/3).Î¼ W cosec Î± (r₁ + r₂)
(C) (1/2). Î¼ W cosec Î± [(r₁³ - r₂³)/(r₁² - r₂²)]
(D) (2/3). Î¼ W cosec Î± [(r³ - r₂³)/(r₁² - r₂²)]

2. The secondary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
(A) 0° and 90°
(B) 180° and 360°
(C) Both (A) and (B)
(D) None of these

3. Which of the following is false statement in respect of differences between machine and structure?
(A) Machines transmit mechanical work, whereas structures transmit forces
(B) In machines, relative motion exists between its members, whereas same does not exist in case of structures
(C) Machines modify movement and work, whereas structures modify forces
(D) Efficiency of machines as well as structures is below 100 %

4. In Meyer's expansion valve, the expansion valve is driven by an eccentric having an angle of advance from
(A) 50°-60°
(B) 60°-70°
(C) 70°-80°
(D) 80°-90°

5. When a body is subjected to transverse vibrations, the stress induced in a body will be
(A) Shear stress
(B) Bending stress
(C) Tensile stress
(D) Compressive stress

6. The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in
(A) Transverse vibrations
(B) Torsional vibrations
(C) Longitudinal vibrations
(D) All of these

7. Klein's construction gives a graphic construction for
(A) Slider-crank mechanism
(B) Velocity polygon
(C) Acceleration polygon
(D) Four bar chain mechanism

8. In the below figure, PC is the connecting rod and OC is the crank making an angle Î¸ with the line of stroke PO and rotates with uniform angular velocity at Ï‰ rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO, if N coincides with O, then

(A) Acceleration and velocity of the piston P is zero
(B) Acceleration and velocity of the piston P is maximum
(C) Acceleration of the piston P is zero and its velocity is maximum
(D) Acceleration of the piston P is maximum and its velocity is zero

9. The Scott-Russell mechanism consists of
(A) Sliding and turning pairs
(B) Sliding and rotary pairs
(C) Turning and rotary pairs
(D) Sliding pairs only

10. The displacement of the D-slide valve is __________ the steam lap by a distance known as lead of the valve.
(A) Greater than
(B) Less than
(C) Equal to
(D) None of these

11. In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.
(A) Equal to
(B) Directly proportional to
(C) Inversely proportional to
(D) Independent of

12. When there is a reduction in amplitude over every cycle of vibration, then the body is said to have
(A) Free vibration
(B) Forced vibration
(C) Damped vibration
(D) Under damped vibration

13. Which of the following statement is correct?
(A) For constant velocity ratio transmission between two gears, the common normal at the point of contact must always pass through a fixed point on the line joining the centers of rotation of gears.
(B) For involute gears, the pressure angle changes with the change in center distance between gears.
(C) The epicyclic gear trains involve rotation of at least one gear axis about some other gear axis.
(D) All of the above

14. In multi V-belt transmission, if one of the belt is broken, we have to change the
(A) Broken belt
(B) Broken belt and its adjacent belts
(C) All the belts
(D) There is no need of changing any one as remaining belts can take care of transmission of load

15. The Coriolis component of acceleration depends upon
(A) Velocity of slider
(B) Angular velocity of the link
(C) Both (A) and (B)
(D) None of these

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