MECHANICAL ENGINEERING QUESTIONS

1.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
a) 8000
b) 6000
c) 4000
d) 1000

2. Environment friendly refrigerant R134 is used in the new generation domestic refrigerators. Its
chemical formula is
a) CHClF2 
b) C2Cl3F3 
c) C2Cl2F4 
d) C2H2F4

3. The number of degrees of freedom of a planar linkage with 8 links and 9 simple revolute joints is
 a) 1 
b) 2 
c) 3 

d) 4

4.A solid circular shaft needs to be designed to transmit a torque of 50 Nm. Ifthe allowable shear
stress of the material is 140 MPa, assuming a factor of
safety of 2, the minimum allowable design diameter is mm is
a) 8 
b) 16
c) 24 
d) 32

5. A carnot engine rejects 30 % of absorbed heat to a sink at 30 °C . The temperature of the heat source is
a)100° C
b) 100K 
c) 737°C 
d) 768° C

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