MCQOPTIONS
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MCQOPTIONS
This section includes 68 Mcqs, each offering curated multiple-choice questions to sharpen your Machine Dynamics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The flywheel stores the potential energy. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2. |
The engine has the flywheel of mass 7 tons and the radius of gyration is 1.7 m. The fluctuation of energy is 55 kN-m. The mean speed of the engine is 150 rpm. What is the coefficient of fluctuation of speed? |
| A. | 0.021 |
| B. | 0.011 |
| C. | 0.031 |
| D. | 0.041 |
| Answer» C. 0.031 | |
| 3. |
The steam engine has a flywheel which is having a radius of gyration of 1.1 m and mass of 2200 kg. The starting torque is 1550 Nm and assumed constant. What is the angular acceleration of the flywheel? |
| A. | 0.54 rad/s2 |
| B. | 0.58 rad/s2 |
| C. | 0.62 rad/s2 |
| D. | 0.52 rad/s2 |
| Answer» C. 0.62 rad/s2 | |
| 4. |
In the single-cylinder, single acting, four-stroke gas engine, the total fluctuation of speed is not to exceed ±3 percent of the mean speed. What is the coefficient of fluctuation of speed? |
| A. | 0.04 |
| B. | 0.03 |
| C. | 0.09 |
| D. | 0.06 |
| Answer» E. | |
| 5. |
Which of the following is the expression of the maximum fluctuation of energy in a flywheel where I = mass moment of inertia of the flywheel, Cs = coefficient of fluctuation of speed, ω = mean angular speed of ω1 and ω2, and E = mean kinetic energy of the flywheel? |
| A. | I*ω*(ω1+ω2) |
| B. | I*ω*Cs |
| C. | 2*E2*Cs |
| D. | I*ω2*Cs |
| Answer» E. | |
| 6. |
What is the coefficient of fluctuation of speed? |
| A. | The ratio of the maximum fluctuation of speed to the mean speed |
| B. | The ratio of the maximum fluctuation of energy to the mean speed |
| C. | The ratio of the minimum fluctuation of energy to the mean speed |
| D. | The ratio of the work done per cycle to the mean speed |
| Answer» B. The ratio of the maximum fluctuation of energy to the mean speed | |
| 7. |
Given that maximum fluctuation of energy is 2000 N-m/s and coefficient of fluctuation of speed is 0.02. What is the mean kinetic energy of flywheel? |
| A. | 50 kN-m/s |
| B. | 40 kN-m/s |
| C. | 30 kN-m/s |
| D. | 20 kN-m/s |
| Answer» B. 40 kN-m/s | |
| 8. |
Which of the following is true about the flywheel? |
| A. | Flywheel regulates speed over a period of time |
| B. | Flywheel takes care of the quantity of fluid |
| C. | Flywheel controls \(\frac{dN}{dt}\) |
| D. | Flywheel regulates the speed by regulating the quantity of charge of the prime mover |
| Answer» D. Flywheel regulates the speed by regulating the quantity of charge of the prime mover | |
| 9. |
What is the coefficient of fluctuation of energy? |
| A. | The ratio of the maximum fluctuation of energy to the minimum fluctuation of energy |
| B. | The ratio of the maximum fluctuation of energy to the work done per cycle |
| C. | The ratio of the minimum fluctuation of energy to the maximum fluctuation of energy |
| D. | The ratio of the work done per cycle to the maximum fluctuation of energy |
| Answer» C. The ratio of the minimum fluctuation of energy to the maximum fluctuation of energy | |
| 10. |
What is the maximum fluctuation of energy? |
| A. | It is the sum of maximum and minimum energies |
| B. | It is the ratio of the maximum and minimum energies |
| C. | It is the ratio of the mean resisting torque to the work done per cycle |
| D. | It is the difference between the maximum and minimum energies |
| Answer» E. | |
| 11. |
The flywheel is accelerated during the |
| A. | AB |
| B. | BC |
| C. | CD |
| D. | Both AB and CD |
| Answer» E. | |
| 12. |
During the portion AB the flywheel is _____ |
| A. | Accelerated |
| B. | Decelerated |
| C. | Maintain constant speed |
| D. | None of the listed |
| Answer» B. Decelerated | |
| 13. |
When the driving torque is more than load torque, flywheel is ______ |
| A. | Accelerated |
| B. | Decelerated |
| C. | Constant velocity |
| D. | Can’t be determined |
| Answer» B. Decelerated | |
| 14. |
Which of the following is not true for cast iron flywheels? |
| A. | Excellent damping |
| B. | Cheap |
| C. | Given complex shape |
| D. | Sudden failure |
| Answer» E. | |
| 15. |
Which of the following doesn’t waste energy? |
| A. | Flywheel |
| B. | Governor |
| C. | Both flywheel and governor |
| D. | Neither flywheel nor governor |
| Answer» B. Governor | |
| 16. |
Is use of a flywheel recommended when a large motor is required only for a small instant of time? |
| A. | True |
| B. | False |
| Answer» B. False | |
| 17. |
The speed of an engine varies from 210 rad/s to 190 rad/s. During the cycle the change in kinetic energy is found to be 400 Nm. The inertia of the flywheel in kg/m2 is |
| A. | 0.1 |
| B. | 0.20 |
| C. | 0.30 |
| D. | 0.40 |
| Answer» B. 0.20 | |
| 18. |
A circular solid disc of uniform thickness 20 mm, radius 200 mm and mass 20 kg, is used as a flywheel. If it rotates at 600 rpm, the kinetic energy of the flywheel, in Joules is |
| A. | 395 |
| B. | 790 |
| C. | 1580 |
| D. | 3160 |
| Answer» C. 1580 | |
| 19. |
The flywheel of a machine having weight of 4500 N and radius of gyration of 2 m has cyclic fluctuation of speed from 125 r.p.m to 120 r.p.m. Assuming g = 10m/s2, the maximum fluctuation of energy is |
| A. | 12822 N-m |
| B. | 24200 N-m |
| C. | 14822 N-m |
| D. | 12100 N-m |
| Answer» E. | |
| 20. |
For a certain engine having an average speed of 1200 rpm, a flywheel approximated as a solid disc, is required for keeping the fluctuation of speed within 2% about the average speed. The fluctuation of K.E per cycle is found to be 2 KJ. What is the least possible mass of the flywheel if it diameter is not exceeding 1 m? |
| A. | 40 kg |
| B. | 51 kg |
| C. | 62 kg |
| D. | 73 kg |
| Answer» C. 62 kg | |
| 21. |
For the same maximum fluctuation energy of a flywheel, if the mean speed of rotation is more |
| A. | the size of the flywheel is reduced |
| B. | the size of the flywheel is increased |
| C. | the size of the flywheel is not dependent on the speed and is unaffected |
| D. | working is safer |
| Answer» B. the size of the flywheel is increased | |
| 22. |
Flywheel absorbs energy during those periods of crank rotation when |
| A. | The twisting moment is greater than the resisting moment |
| B. | The twisting moment is equal to the resisting moment |
| C. | The twisting moment is less than the resisting moment |
| D. | The load on the engine falls |
| Answer» B. The twisting moment is equal to the resisting moment | |
| 23. |
In which one of the following is a fly wheel generally employed |
| A. | Lathe |
| B. | Electric motor |
| C. | Punching machine |
| D. | Gear box |
| Answer» D. Gear box | |
| 24. |
A flywheel is fitted to the crank shaft of an engine having W amount of indicated work per revolution. Permissible limits of coefficient of fluctuation of energy and speed are CE and CS respectively. The kinetic energy of the flywheel is given by |
| A. | \(2\frac{{W \cdot {C_E}}}{{{C_S}}}\) |
| B. | \(\frac{{W \cdot {C_E}}}{{{2C_S}}}\) |
| C. | \(\frac{{W \cdot {C_E}}}{{{C_S}}}\) |
| D. | \(\frac{{W \cdot {C_s}}}{{{2C_E}}}\) |
| Answer» C. \(\frac{{W \cdot {C_E}}}{{{C_S}}}\) | |
| 25. |
In a flywheel, the value of safe stress is 25 MNm-2 and density of material is 10000 kgm-3. The maximum peripheral velocity will be |
| A. | 200 ms-1 |
| B. | 100 ms-1 |
| C. | 50 ms-1 |
| D. | 25 ms-1 |
| Answer» D. 25 ms-1 | |
| 26. |
Pick up the wrong statement. A flywheel |
| A. | Is used to limit the inevitable fluctuation of speed during each cycle |
| B. | Controls the mean speed of rotation |
| C. | Stores up energy and gives up whenever required |
| D. | Regulates the speed during one cycle of a prime mover |
| Answer» C. Stores up energy and gives up whenever required | |
| 27. |
If C1 is the coefficient of speed fluctuation of a flywheel then the ratio of ωmax/ ωmin will be: |
| A. | \(\frac{{1 - 2{C_1}}}{{1 + 2{C_1}}}\) |
| B. | \(\frac{{2 - {C_1}}}{{2 + {C_1}}}\) |
| C. | \(\frac{{1 + 2{C_1}}}{{1 - 2{C_1}}}\) |
| D. | \(\frac{{2 + {C_1}}}{{2 - {C_1}}}\) |
| Answer» E. | |
| 28. |
A flywheel connected to a punching machine has to supply energy of 400 Nm while running at a mean angular speed of 20 radians/s. If the total fluctuation of speed is not to exceed ±2%, the mass moment of inertia of the flywheel in kg – m2 is |
| A. | 25 |
| B. | 50 |
| C. | 100 |
| D. | 125 |
| Answer» B. 50 | |
| 29. |
A three-cylinder single-acting engine has its cranks at 120°. The turning moment diagram for each cycle is a triangle for the power stroke with a maximum torque of 60 Nm at 60° after the dead centre of the corresponding crank. There is no torque on the return stroke. The engine runs at 400 r.p.m. The power developed will be |
| A. | 1745 W |
| B. | 1885 W |
| C. | 1935 W |
| D. | 1995 W |
| Answer» C. 1935 W | |
| 30. |
If a flywheel having mass of 100 kg and radius of gyration 10 cm is rotating at 10 rad/s, its rotational kinetic energy will be |
| A. | 10 J |
| B. | 25 J |
| C. | 50 J |
| D. | 100 J |
| Answer» D. 100 J | |
| 31. |
If the speed of the engine fluctuates between 990 rpm and 1010 rpm in a cycle operation, the coefficient of fluctuation of speed is: |
| A. | 0.05 |
| B. | 0.01 |
| C. | 0.02 |
| D. | 0.04 |
| Answer» D. 0.04 | |
| 32. |
A steam engine develops 600 kW at 180 r.p.m. The coefficient of fluctuation of energy is found to be 0.5 and the fluctuation of speed is required to be kept within ±1% of the mean speed. The maximum fluctuation of the energy during operation is given by: |
| A. | 150 kN-m |
| B. | 50 kN-m |
| C. | 100 kN-m |
| D. | 120 kN-m |
| Answer» D. 120 kN-m | |
| 33. |
For the same mass of flywheel |
| A. | the disc type flywheel is preferable |
| B. | the rim type flywheel is preferable |
| C. | preference will depend upon the type of the prime mover |
| D. | any type is equally preferable |
| Answer» C. preference will depend upon the type of the prime mover | |
| 34. |
For flywheel the formula \(\frac{Iω^2}{2}\) shows |
| A. | Torque |
| B. | Kinetic energy |
| C. | Angular momentum |
| D. | Centrifugal force |
| Answer» C. Angular momentum | |
| 35. |
If a flywheel has a mass moment of inertia I, rotating at a mean speed ω, kinetic energy is E and coefficient of fluctuation of speed is K, then maximum fluctuation of energy in a flywheel will be equal to |
| A. | Iω2K |
| B. | 2KE |
| C. | Iω(ω1 – ω2) |
| D. | All of the above |
| Answer» E. | |
| 36. |
A solid cast iron disk, 1 m in diameter and 0.2 m thick, is used as a flywheel. It is rotating at 350 rpm. It is brought to rest in 1.5 s by means of a brake. If the mass density of cast iron is 7200 kg/m3, the torque exerted by the brake will be nearly |
| A. | 3.5 kNm |
| B. | 4.5 kNm |
| C. | 5.3 kNm |
| D. | 6.3 kNm |
| Answer» B. 4.5 kNm | |
| 37. |
A turning moment diagram of the four-stroke engine as shown in the given diagram with the mean torque (Tm) of 20 Nm. What is the value of estimate peak torque (Tp) in (Nm), if the negative torque is to be neglected? |
| A. | 80 |
| B. | 120 |
| C. | 140 |
| D. | 160 |
| Answer» E. | |
| 38. |
An engine, as the prime mover must have both flywheel and a governor provided in the system for which of the following purposes? |
| A. | For increasing the speed |
| B. | For minimizing the speed fluctuations |
| C. | For maximizing the speed fluctuations |
| D. | None of these |
| Answer» C. For maximizing the speed fluctuations | |
| 39. |
If the speed of an engine varies between 390 and 410 rpm in a cycle of operation, the coefficient of fluctuations of speed would be |
| A. | 0.01 |
| B. | 0.02 |
| C. | 0.04 |
| D. | 0.05 |
| Answer» E. | |
| 40. |
A circular solid disc of uniform thickness 20 mm, radius 200 mm and mass 20 kg, is used as flywheel. If it rotates at 600 rpm, the kinetic energy of the flywheel, in joules is |
| A. | 395 |
| B. | 790 |
| C. | 1580 |
| D. | 3160 |
| Answer» C. 1580 | |
| 41. |
Maximum fluctuation of energy is the |
| A. | Sum of maximum and minimum energies |
| B. | Difference between maximum and minimum energies |
| C. | Ratio of maximum and minimum energies |
| D. | Ratio of mean resisting torque to the work done per cycle |
| Answer» C. Ratio of maximum and minimum energies | |
| 42. |
In a 4-stroke IC engine, the turning moment during the compression stroke is |
| A. | Positive throughout |
| B. | Negative throughout |
| C. | Positive during major portion of the stroke |
| D. | Negative during major portion of the stroke |
| Answer» C. Positive during major portion of the stroke | |
| 43. |
For finding out the bending moment for the arm (spoke) of flywheel, the arm is assumed as |
| A. | A cantilever beam fixed at the rim and subjected to tangential force at the hub |
| B. | A simply supported beam fixed at hub and rim and carrying uniformly distributed load |
| C. | A cantilever beam fixed at the hub and subjected to tangential force at the rim |
| D. | A fixed beam fixed at hub and rim and carrying uniformly distributed load |
| Answer» E. | |
| 44. |
A circular disc of uniform thickness 10 mm, radius 100 mm and mass 10 kg is used as a flywheel. If it rotates a 600 rpm the kinetic energy of flywheel is |
| A. | 98.70 J |
| B. | 49.35 J |
| C. | 24.67 J |
| D. | 197.39 J |
| Answer» B. 49.35 J | |
| 45. |
A riveting machine is driven by a constant-torque 3kW motor. The moving parts including the flywheel are equivalent to 150 kg at 0.6 m radius. One riveting operation takes 1 second and absorbs 10000 N-m of energy. The speed of the flywheel is 300 r.p.m. before riveting. What is the speed (to nearest 10 r.p.m.) after riveting and what is the number of rivets that can be closed per minute? |
| A. | 260 r.p.m. and 18 |
| B. | 290 r.p.m. and 15 |
| C. | 360 r.p.m. and 18 |
| D. | 390 r.p.m. and 15 |
| Answer» B. 290 r.p.m. and 15 | |
| 46. |
A circular disk of uniform thickness 20 mm, radius 100 mm and mass 20 kg is used a s flywheel. If it rotates at 600 rpm, kinetic energy of flywheel is Joule is |
| A. | 395 |
| B. | 790 |
| C. | 1580 |
| D. | 3160 |
| Answer» B. 790 | |
| 47. |
THE_FLYWHEEL_OF_A_MACHINE_HAVING_WEIGHT_OF_4500_N_AND_RADIUS_OF_GYRATION_OF_2_M_HAS_CYCLIC_FLUCTUATION_OF_SPEED_FROM_125_R.P.M_TO_120_R.P.M._ASSUMING_G_=_10M/S2,_THE_MAXIMUM_FLUCTUATION_OF_ENERGY_IS?$ |
| A. | 12822 N-m |
| B. | 24200 N-m |
| C. | 14822 N-m |
| D. | 12100 N-m |
| Answer» E. | |
| 48. |
WHICH_OF_THE_FOLLOWING_IS_NOT_TRUE_FOR_CAST_IRON_FLYWHEELS??$ |
| A. | Excellent damping |
| B. | Cheap |
| C. | Given complex shape |
| D. | Sudden failure |
| Answer» E. | |
| 49. |
THE_RATIO_OF_MAXIMUM_FLUCTUATION_OF_SPEED_TO_THE_MEAN_SPEED_IS_CALLED?$ |
| A. | fluctuation of energy |
| B. | maximum fluctuation of energy |
| C. | coefficient of fluctuation of speed |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 50. |
The speed of an engine varies from 210 rad/s to 190 rad/s. During the cycle the change in kinetic energy is found to be 400 Nm. The inertia of the flywheel in kg/m2 is$ |
| A. | 0.10 |
| B. | 0.20 |
| C. | 0.30 |
| D. | 0.40 |
| Answer» B. 0.20 | |