Tag: general knowledge

In rigid flanged couplings, bolts primarily experience shear force due to torque transmission between shafts and bending moment from any misalignment or external loads. The bolts don't directly carry torsional loads - that's what the shafts transmit.

Surface tension minimizes surface area, causing small water droplets to form spherical shapes. For falling rain drops, air resistance distorts this ideal shape, but surface tension is the fundamental reason for sphericity.

Hydrostatic lubrication maintains a complete fluid film even at zero speed by externally pressurizing the lubricant, giving very low starting friction. Hydrodynamic lubrication relies on relative motion to generate pressure film, so starting friction is higher.

Bernoulli's equation requires steady, incompressible, inviscid flow along a streamline. Turbulent flow is unsteady by definition and involves significant energy dissipation due to eddies, violating Bernoulli's assumptions. Rotational flows can also violate the irrotational requirement.

The Acme thread has a trapezoidal profile with sides inclined at 29°, designed for power transmission and easy manufacturing. Square threads have rectangular profiles, while buttress threads are asymmetric for unidirectional loads.

In metal cutting, material removal occurs through intense shear deformation along the shear plane. The cutting tool creates high stresses that cause the material to fail in shear, forming chips that curl away. This is a plastic deformation process, not linear translation.

Spherical roller bearings have a self-aligning feature due to their spherical raceway geometry, which accommodates misalignment between shaft and housing. Roller and needle roller bearings don't have this capability.

Kaplan turbine is a propeller-type reaction turbine with adjustable blades, designed for low-head applications. It's an axial flow turbine (water flows parallel to shaft), not mixed or outward flow. The 'low' in option B likely means 'low-head' despite the grammatical issue.