# GATE Questions & Answers of Rolling and Sliding Contact Bearings

## What is the Weightage of Rolling and Sliding Contact Bearings in GATE Exam?

Total 9 Questions have been asked from Rolling and Sliding Contact Bearings topic of Machine Design subject in previous GATE papers. Average marks 1.67.

A self-aligning ball bearing has a basic dynamic load rating ($C_{10}$, for $10^6$ revolutions) of 35 kN. If the equivalent radial load on the bearing is 45 kN, the expected life (in $10^6$ revolutions) is

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Three masses are connected to a rotating shaft supported on bearings A and B as shown in figure. The system is in space where the gravitation effect is absent. Neglect the mass of shaft and rods connecting the masses. For m= 10 kg, m= 5 kg and m= 2.5 kg and for a shaft angular speed of 1000 radian/s, the magnitude of the bearing reaction (in N) at location B is_________

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Which of the bearings given below SHOULD NOT be subjected to a thrust load?

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For ball bearings, the fatigue life L measured in number of revolutions and the radial load F are related by FL1/3=K, where K is a constant. It withstands a radial load of 2 kN for a life of 540 million revolutions. The load (in kN) for a life of one million revolution is__________

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A hydrodynamic journal bearing is subject to 2000 N load at a rotational speed of 2000 rpm. Both bearing bore diameter and length are 40 mm. If radial clearance is 20 μm and bearing is lubricated with an oil having viscosity 0.03 Pa.s, the Sommerfeld number of the bearing is _______

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Ball bearings are rated by a manufacturer for a life of 106 revolutions. The catalogue rating of a particular bearing is 16 kN. If the design load is 2 kN, the life of the bearing will be p× 106 revolutions, where p is equal to ______

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Two identical ball bearings P and Q are operating at loads 30 kN and 45 kN respectively. The ratio of the life of bearing P to the life of bearing Q is

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A ball bearing operating at a load F has 8000 hours of life. The life of the bearing, in hours, when the load is doubled to 2F is

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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 Sommerfeld number for the bearing is