DME-II A-4
Question No : 1
A cylindrical roller bearing with bore diameter of 45mm is subjected to a radial force of 50kN. The coefficient of friction is 0.0012 and the speed of rotation is 1440 r.p.m. Calculate the power lost in friction.
0.5055KW
0.2035KW
3.2055KW
5.5520KW
Question No : 2
A ball bearing is subjected to a radial force of 3000N and an axial force of 1500N. The dynamic load carrying capacity of the bearing is 7550N. The values of X and Y factors are 0.56 and 1.6 respectively. The shaft is rotating at 720r.p.m. Calculate the life of the bearing in hours.
546
36
146
86
Question No : 3
A journal bearing 60mm in diameter and 90mm long runs at 450r.p.m. The oil used for hydrostatic lubrication has absolute viscosity of 0.06 kg/m-s. If the diametral clearance is 0.1mm, find the safe load on the bearing.
3672N
1672N
5672N
72N
Question No : 4
Brakes convert
heat energy into kinetic energy
kinetic energy or potential energy into heat energy
heat energy into potential energy
kinetic energy into potential energy
Question No : 5
The hydrostatic thrust bearing of a generator consists of six pads. The total thrust load is 900KN and film thickness is 0.05mm. The viscosity of the lubricant is 300SUS. Neglecting the flow over corners, each can be approximated as a circular area of 500mm and 100mm as outer and inner diameters respectively. Then density of the lubricating oil is 0.9gm/cc. calculate the flow requirement in mm3/sec
12985
10985
22985
98425
Question No : 6
A sliding bearing which can support steady loads without any relative motion between the journal and the bearing is called
zero film bearing
boundary lubricated bearing
hydrodynamic lubricated bearing
hydrostatic lubricated bearing
Question No : 7
Teflon is used for bearings because of
better heat dissipation
smaller space consideration
low coefficient of friction
all
Question No : 8
The ball bearings are usually made from
chrome nickel steel
low carbon steel
medium carbon steel
high speed steel
Question No : 9
The piston pin bearings in heavy duty diesel engines are
tapered roller bearings
needle roller bearings
spherical roller bearings
cylindrical roller bearings
Question No : 10
Figure shows the arrangement of two brake shoes which act on the internal surface of a cylindrical brake drum. The braking force F1 and F2 are applied as shown and each shoe pivots on its fulcrum O1 and O2. The width of the brake lining is 35 mm. The intensity of pressure at any point A is 0.4 sin ? N/mm2, where ? is measured as shown from either pivot. The coefficient of friction is 0.4. Determine the braking torque and the magnitude of the forces F1 and F2.
285N, 700N
685N, 2323N
1250N, 8000N
100N, 580N
 
Designed by
Dr.M.Raja Roy
            M.E.,Ph.D
Associate Professor
Mechanical Engg. Dept
ANITS