11) Which one of the following frictions occurs in an un-lubricated journal bearing ?

Sliding friction

Rolling friction

Fluid friction

Dry friction

Answer is:

Dry friction

Explanation:

Dry friction occurs in an un-lubricated journal bearing.

Tool steel

Grey cast iron

Copper

Aluminium

Answer is:

Explanation:

In Grey cast iron materials no cutting oil is used when drilling.

Cutting oil

Grease

Lard oil

Kerosene oil

Answer is:

Explanation:

when cutting steel with hand hacksaw, cutting oil is used .

Carry away the heat produced in bearing

Prevent metal-to-metal contact and reduce friction

Prevent entry of foreign material i.e dust, dirt etc. in the bearing

Provide a cushion to a load and shocks

Answer is:

No change in viscosity due to variation in temperature

Reduces friction between machine parts

Takes up the surface pressure between sliding parts

Becomes thicker after prolonged use

Answer is: