What is the difference between Bolt and Screw?

The main difference was based on the load acting on it, and the size. For smaller loads, screws are enough but in case of greater-loads, bolts are to be used. In bolt we give centrifugal force or tangential force and screw we give axial force for driving.

Which is heavier 1kg of Iron or 1kg of Cotton? and why?

Both of them have same weight. The only difference is the volume of Iron is small compared to Cotton.

How to measure Temperature of a Bearing?

Normally the temperature range from 80 degree to 110 degree Celsius. So the following temperature measurement devices are used.

· Dial Type Bearing Temperature Detector

· Stator Winding Temperature Detector

· Resistance Bearing Temperature Detector (Bearing RTD)

· Specialized in Pin type RTD