In which of the following bearings, the bearing pressure is acting perpendicular to the axis of shaft?

Explanation: 

Bearings:

• Bearings are used in parts having relative motion.
• The motion may be rotational, reciprocating, or a combination of these movements.
• Bearings form part of an assembly or mechanism which supports or constrains another part in the assembly.

Bearings are generally grouped as:

• Plain bearings
• Anti-friction bearings.

Plain bearings:

• Depending on the direction of the load application they are called radial or journal bearings and thrust bearings.
• These bearings have a cylindrical shape and are fitted in a housing.
• Plain bearings are kept in position without allowing them to rotate along with the shaft.
• For this purpose, they are press-fitted in the housing or provided with a key or screws.

Thrust bearing:

• In this, the loading is parallel to the bearing axis.
• The Thrust bearing supports the load acting along the axis of the shaft.
• They are designed to support a predominantly axial load.

Radial or journal bearing:

• In this, the loading is at right angles to the bearing axis.

There are two types of thrust bearings which take axial load, namely 

1. Footstep: The footstep bearing or simply 'step' bearing is a thrust bearing in which the end of the shaft is in contact with the bearing surface.
2. Collar: The collar bearing is a thrust bearing in which a collar integral with the shaft is in contact with the bearing surface.

Hydrodynamic lubrication is defined as a system of lubrication in which the load-supporting fluid film is created by the shape and relative motion of the sliding surface.

Hydrostatic lubrication is defined as a system of lubrication in which the load-supporting fluid film, separating the two surfaces is created by an external source, like a pump, supplying sufficient fluid under pressure.