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# BARC 2021 ME: Subject Revision Quiz 6

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Question 1

A disk clutch is required to transmit 5 kW at 2000 rpm. The disk has a friction lining with coefficient of friction equal to 0.25 and bore radius of friction lining is equal to 25 mm. assume uniform contact pressure of 1 MPa. The value of outside radius of the friction lining is:

Question 2

The number of degrees of freedom of the planetary gear train shown in the figure is

Question 3

A rigid link PQ is undergoing plane motion as shown in the figure (VPand VQare non=zero). VPQ is relative velocity of point Q with respect to point P.

Which one of the following is TRUE?

Question 4

The whal factor (k) is

(where ‘C’ is ratio of mean diameter to wire diameter of a spring)

Question 5

In a slider-crank mechanism, the lengths of the crank and the connecting rod are 10mm and 160mm, respectively. The crank is rotating with an angular of 10 radian/s counter-clockwise. The magnitude of linear velocity (in m/s) of the piston at the instant corresponding to the configuration shown in the figure is _____.

Question 6

Which of the following is a function of oldham’s coupling:

Question 7

The bearing has its radial clearance changed from 0.025 mm to 0.015 mm. If the viscosity of oil is 0.045 kg/ms, what should its viscosity after change in radial clearance.

Question 8

A forged steel link with uniform diameter of 30 mm at the centre is subjected to an axial force that varies from 40 kN in compression to 160 kN in tension. The tensile (Su), yield (Sy) and corrected endurance (Se) strengths of the steel material are 600 MPa, 420 MPa and 240 MPa respectively. The factor of safety against fatigue endurance as per Soderberg’s criterion is

Question 9

In an open arm watt Governor upper links length is 350 mm and lower link length is 250 mm. At an instant upper links makes angle of 45° with the vertical. Find the radius of rotation ________ (in mm). If rotation speed is 300 rpm.

Question 10

A shaft of 300 mm diameter is carrying a load of 20 kN at 2000 rpm. A bearing of 450 mm length supporting the shaft. The absolute viscosity of lubricating oil is 0.011 kg/m-s at the operating temperature and diametral clearance of the bearing is 0.30 mm. The power loss( in kW) in bearing due to friction will be

Question 11

In a certain slider-crank mechanism, lengths of crank and connecting rod are equal. If the crank rotates with a uniform angular speed of 14 rad/s and the crank length is 300 mm, the maximum acceleration of the slider (in m/s2) is _______.

Question 12

A precision instrument package (m = 1 kg) needs to be mounted on a surface vibrating at 60 Hz. It is desired that only 5% of the base surface vibration amplitude be transmitted to the instrument. Assume that the isolation is designed with its natural frequency sig lesser than 60 Hz, so that the effect of damping may be ignored. The stiffness (in N/m) of the required mounting pad is

Question 13

A machine part of mass 5 kg vibrates in a viscous medium. Determine the damping coefficient (in N-s/m) when a harmonic exciting force of 10 N results in a resonant amplitude of 10 mm with a period of 0.5 second.

Question 14

What is the mechanical advantage for a four bar linkage in toggle position?

Question 15

A spherical vessel of a1000 mm inner diameter is subjected to an internal pressure which varies from 5 MPa to 10 MPa. The material of the vessel is cold drawn steel having ultimate strength 450 MPa and yield strength 240 MPa. If the reliability of the vessel is 90% and required factor of safety is 2, the thickness of pressure vessel for an infinite life period is _____ mm.

Question 16

A spur pinion of pitch diameter 50 mm rotates at 200 rad/s and transmits 3 kW power. The pressure angle of the tooth of the pinion is 20 °. Assuming that only one pair of the teeth is in contact, the total force (in newton) exerted by a tooth of the pinion on the tooth on a mating gear is ________

Question 17

A natural feed journal bearing of diameter 50 mm and length 50 mm operating at 20 revolution/second carries a load of 2.0 k N. The lubricant used has a viscosity of 20 mPa s. The radial clearance is 50 μm. The Somerfield number for the bearing is

Question 18

A force of 400 N is applied to the brake drum of 0.5 m diameter in a band-brake system as shown in the figure, where the wrapping angle is 180 °. If the coefficient of friction between the drum and the band is 0.25, the braking torque applied, in N.m is

Question 19

A shaft is transmitting power at 225 rpm while the expected life of bearing is 10,000 hour, the life of bearing in million revolutions per hour is

Question 20

A car of mass 1000 kg is moving down the hill at a slope of 1: 4 at 108 km/hr. The braking torque(in Nm) to be applied to stop the vehicle in a distance of 100 m, is _______ . Diameter of tyre is 0.5m (Neglect all the frictional energy except for the brake)
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