Description : The coefficient of fluctuation of speed of flywheel is 1. ratio of maximum and minimum speeds during the cycle 2. ratio of maximum fluctuation of speed to the mean speed 3. ratio of mean ... maximum fluctuation of speed during the cycle 4. sum of maximum fluctuation of speed and the mean speed
Last Answer : 2. ratio of maximum fluctuation of speed to the mean speed
Description : The difference the maximum and minimum speeds during a cycle is called (A) Fluctuation of speed (B) Maximum fluctuation of speed (C) Coefficient of fluctuation of speed (D) None of the above
Last Answer : (B) Maximum fluctuation of speed
Description : The coefficient of fluctuation of speed of flywheel is, (A) Ratio of maximum and minimum speeds during the cycle (B) Ratio of maximum fluctuation of speed to the mean speed (C) Ratio of ... maximum fluctuation of speed during the cycle (D) Sum of maximum fluctuation of speed and the mean speed
Last Answer : (B) Ratio of maximum fluctuation of speed to the mean speed
Description : The maximum fluctuation of speed of flywheel is, (A) Difference between maximum and minimum speeds during the cycle (B) Difference between maximum and mean speeds during the cycle (C) Difference ... and minimum speeds during the cycle (D) Mean of maximum and minimum speeds during the cycle
Last Answer : (A) Difference between maximum and minimum speeds during the cycle
Description : Calculate the coefficient of fluctuation of speed if maximum speed is 2500rpm and minimum speed is 1800rpm. 1. 1.44 2. 1.33 3. 0.33 4. 0.44
Last Answer : 3. 0.33
Description : In an oil-lubricated journal bearing, coefficient of friction between the journal and the bearing. [IES-1995] (a) Remains constant at all speeds. (b) is minimum at zero speed and increases ... speed. (d) becomes minimum at an optimum speed and then increases with further increase in speed.
Last Answer : (d) becomes minimum at an optimum speed and then increases with further increase in speed.
Description : The coefficient of fluctuation of energy of flywheel is 1. ratio of maximum fluctuation of energy to work done per cycle 2. ratio of to work done per cycle to maximum fluctuation of energy ... minimum kinetic energy during the cycle 4. ratio of maximum and minimum kinetic energy during the cycle
Last Answer : 1. ratio of maximum fluctuation of energy to work done per cycle
Description : The coefficient of fluctuation of energy of flywheel is, (A) Ratio of maximum fluctuation of energy to work done per cycle (B) Ratio of to work done per cycle to maximum fluctuation of ... minimum kinetic energy during the cycle (D) Ratio of maximum and minimum kinetic energy during the cycle
Last Answer : (A) Ratio of maximum fluctuation of energy to work done per cycle
Description : Reciprocal of coefficient of fluctuation of speed is called 1. fluctuation of energy 2. fluctuation of speed 3. maximum fluctuation of speed 4. coefficient of fluctuation of speed
Last Answer : 4. coefficient of fluctuation of speed
Description : The coefficient of fluctuation of energy = (A) Maximum fluctuation of energy / work done per cycle (B) Fluctuation of energy / Work done per cycle (C) Maximum fluctuation of energy / Mean speed (D) Fluctuation of energy / Mean speed
Last Answer : (A) Maximum fluctuation of energy / work done per cycle
Description : Reciprocal of Coefficient of fluctuation of speed is called (A) Fluctuation of speed (B) Coefficient of steadiness (C) Maximum fluctuation of speed (D) None of the above
Last Answer : (B) Coefficient of steadiness
Description : The ratio of maximum fluctuation of speed to the mean speed is called (A) Fluctuation of speed (B) Maximum fluctuation of speed (C) Coefficient of fluctuation of speed (D) None of the above
Last Answer : (C) Coefficient of fluctuation of speed
Description : Different types of bearings are designed to operate at different operating speeds. Speed is specified as the maximum (a) rpm (b) metres/second (c) metres/minute (d) metres/hour
Last Answer : (b) metres/second
Description : A flywheel of moment of inertia 9.8kgm 2 fluctuates by 30 rpm for a fluctuation in energy of 1936 joules. The means speed of flywheel is (in rpm) 1. 600 2. 900 3. 968 4. 2940
Last Answer : 1. 600
Description : The coefficient of fluctuation of speed of Flywheel is given by 1. (N1-N2)/N 2. (N1+N2)/N 3. (N1-N2) x N
Last Answer : 1. (N1-N2)/N
Description : The coefficient of fluctuation of speed of flywheel is given by, (A) (ωmax - ωmin)/ω (B) 2 (ωmax - ωmin)/ (ωmax + ωmin) (C) 2 (nmax - nmin)/ (nmax + nmin) (D) Any one of the above
Last Answer : (D) Any one of the above
Description : The maximum fluctuation of energy of flywheel is 1. difference between maximum and minimum kinetic energy during the cycle 2. difference between maximum and mean kinetic energy during the cycle 3. ... kinetic energy during the cycle 4. mean of maximum and minimum kinetic energy during the cycle
Last Answer : 1. difference between maximum and minimum kinetic energy during the cycle
Description : The maximum fluctuation of energy of flywheel is, (A) Difference between maximum and minimum kinetic energy during the cycle (B) Difference between maximum and mean kinetic energy during the cycle ... kinetic energy during the cycle (D) Mean of maximum and minimum kinetic energy during the cycle
Last Answer : (A) Difference between maximum and minimum kinetic energy during the cycle
Description : A sliding contact bearing is operating under stable condition. The pressure developed in oil film is p when the journal rotates at N rpm. The dynamic viscosity of lubricant is μ and effective coefficient of ... to p and f) (d) f is directly proportional to μ and inversely proportional to N
Last Answer : (b) f is directly proportional to μ and N
Description : A flywheel connected to a punching machine has to supply energy of 400 Nm while running at a mean angular speed of 20 rad/s. If the total fluctuation of speed is not exceed to in kgm 2 is 1. 25 2. 50 3. 100 4. 125
Last Answer : 1. 25
Description : A flywheel is used 1. to limit the fluctuation of speed during each cycle 2. to control the mean speed of the engine 3. to maintain a constant speed 4. to come into action when the speed varies
Last Answer : 1. to limit the fluctuation of speed during each cycle
Description : Maximum fluctuation of energy = 1. Max KE – Min KE 2. Max KE + Min KE 3. Max KE > Min KE 4. Max KE < Min KE
Last Answer : 1. Max KE – Min KE
Description : Maximum fluctuation of energy = (A) Max. KE – Min. KE (B) Max. KE + Min. KE (C) (Max. KE – Min. KE)/2 (D) (Max. KE + Min. KE)/2
Last Answer : (A) Max. KE – Min. KE
Description : The temperature coefficient of copper is `0.004^(@)C^(-1)`. Find the resistance of a 5 m long copper wire of diameter 0.2 mm at `100^(@)C`, if the res
Last Answer : The temperature coefficient of copper is `0.004^(@)C^(-1)`. Find the resistance of a 5 m long copper wire of ... `0^(@)C` is `1.7xx10^(-8) Omega` m.
Description : In hydrodynamic lubrication, film thickness remains unaffected by change in speeds. a) True b) Increase with increase in speed c) Decrease with increase in speed d) Disappear as the speed tends to infinty
Last Answer : b) Increase with increase in speed
Description : A full journal bearing having clearance to radius ratio of 1/100, using a lubricant with μ=28×10-3 Pa s supports the shaft journal running at N = 2400 rpm If bearing pressure is 1.4 MPa, the Somerfield number is [IES-2001] (a) 8×10-3 (b) 8×10-5 (c) 0.48 (d) 0.48×10
Last Answer : (a) S = (μN s /p) (r/c) 2
Description : Satisfactory hydrodynamic film in a journal bearing is formed when (a) Journal speed is low; unit pressure on the bearing is high and viscosity of lubricant used is low [IES-2006] ... journal speed, unit pressure on bearing and lubricant viscosity exists resulting in low coefficient of friction
Last Answer : (c) Journal speed is high; unit pressure on the bearing is high and viscosity of lubricant used is high
Description : Consider tile following statements: [IES-1993; 2002; 2006] Radius of friction circle for a journal bearing depends upon 1. Coefficient of friction 2. Radius of the journal 3. Angular speed of rotation of the shaft Which of the ... ) 1,2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 (d) Only 1 and 3
Last Answer : (b) Only 1 and 2
Description : Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the ... 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3
Last Answer : (b) 1 and 3 only
Description : A circular solid 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 1. 395 2. 790 3. 1580 4. 3160
Last Answer : 2. 790
Description : Calculate the bearing life if expected life for 90% bearings is 9000 hr and the shaft is rotating at 1500 rpm. (a) 850 million rev (b) 810 million rev (c) 810 hr (d) 850 hr
Last Answer : (b) 810 million rev
Description : The static load is defined as the load acting on the bearing when the shaft is _____. (a) stationary (b) rotating at rpm
Last Answer : (a) stationary
Description : The antifriction bearings (a) have low starting and low running friction at moderate speeds (b) have a high initial cost (c) can carry both radial and thrust loads (d) all the mentioned
Last Answer : (d) all the mentioned
Description : The rolling contact bearings as compared to sliding contact bearings have (a) small overall dimensions (b) accuracy of shaft alignment (c) low starting and low running friction except at very high speeds (d) all the mentioned
Description : What is the main advantage of hydrodynamic bearing over roller bearing? (a) Easy to assemble [IES-2005] (b) Relatively low price (c) Superior load carrying capacity at higher speeds (d) Less frictional resistance
Last Answer : (c) Superior load carrying capacity at higher speeds
Description : Static load is defined as the load acting on the bearing when shaft is _____ a) Stationary b) Rotating at rpm
Last Answer : a) Stationary
Description : A bushed-pin type flange coupling is used (A) For intersecting shafts (B) When the shafts are not in exact alignment (C) For small shafts rotating at slow speeds (D) For parallel shafts
Last Answer : (B) When the shafts are not in exact alignment
Description : If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm2. a) 27mm b) 25mm c) 23mm d) 21mm
Last Answer : a) 27mm
Description : If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. a) 51234.4N b) 45968.3N c) 41666.7N d) None of the listed
Last Answer : c) 41666.7N
Description : Define coefficient of fluctuation of energy.
Last Answer : Definition of Coefficient of Fluctuation of Energy: It may be defined as the ratio of the maximum fluctuation of energy to the work done per cycle. Mathematically it is expressed as;
Description : Ultracentrifuges running at speeds upto 100000 rpm is normally used for the (A) Separation of isotopes based on their density or molecular weights difference (B) Concentration of rubber latex (C) Separation of cream from milk (D) Dewaxing of lubricating oil
Last Answer : (A) Separation of isotopes based on their density or molecular weights difference (B) Conc
Description : A journal bearing with hydrodynamic lubrication is running steadily with a certain amount of minimum film thickness. When the load and speed are doubled, how does the minimum film thickness vary? [IES-2008 ... Gets reduced to one-fourth of original value (d) Gets reduced to half of original value
Last Answer : (a) Remains unchanged
Description : The listed life of a rolling bearing, in a catalog is the, (a) minimum expected life (b) maximum expected life (c) average life (d) none of the mentioned
Last Answer : (a) minimum expected life
Description : The stress which vary from a minimum value to a maximum value of the same nature (i.e. tensile or compressive) is called (a) repeated stress (b) yield stress (c) fluctuating stress (d) alternating stress
Last Answer : (c) fluctuating stress
Description : The shaft is always stepped with ________ diameter at the middle portion and __________ diameter at the shaft ends. a) Minimum, maximum b) Maximum, minimum c) Minimum, minimum d) Zero, infinity
Last Answer : b) Maximum, minimum
Description : Principal planes are those planes on which a. Normal stress is maximum b. Normal stress is minimum c. Normal stress is either maximum or minimum d. Shear stress is maximum
Last Answer : c. Normal stress is either maximum or minimum
Description : Principal stresses are a. Firstly Maximum and minimum shear stresses b. Secondly Maximum and minimum normal stresses c. Both (a) & (b) d. None
Last Answer : b. Secondly Maximum and minimum normal stresses
Description : Assertion (A): Oil as a cutting fluid result in a lower coefficient of friction. Reason (R): Oil forms a thin liquid film between the tool face and chip, and it provides 'hydrodynamic lubrication'. [IES- 2000] (a ... explanation of A (c) A is true but R is false (d) A is false but R is true
Last Answer : (c) A is true but R is false
Description : Which of the following are not true for petroff’s equation? a) Shaft is considered concentric with the bearing b) Bearing is subjected to light load c) Is used to find coefficient of friction d) Frictional torque is given by fpr2l
Last Answer : d) Frictional torque is given by fpr2l