Explanation

• Free vortex — rotation driven by gravity, no external energy input, velocity increases toward the center
• Example of a free vortex: water swirling down a drain

Additional information 

• Forced vortex — rotation driven by an external force (like a rotating impeller), velocity increases with radius

Explanation

• By the middle-third rule, the resultant must fall within the middle third of the base
• Max allowable eccentricity e=B/6 to avoid tension
• Keeps entire foundation in compression

Additional information 

• B/4: This would allow tension over part of the base.

Explanation

• Fly ash replaces cement (Portland cement)
• Because it has pozzolanic properties (reacts with lime + water to form cementitious compounds)
• Improves workability, durability, long-term strength; reduces heat of hydration

Explanation

• The coefficient of friction is generally greatest for Rock 
• Rock — highest friction due to angular, rough, interlocking mineral surfaces

Additional information

• Sand — moderate, since grains are more rounded and can roll over each other
• Clay — lower, because fine clay particles are smooth and can also hold water, which lubricates
• Silt — lowest, being very fine, smooth particles

Explanation

• Punching shear is maximum at the Critical section around the column
• Located at a distance of d/2 (half the effective depth of the slab) from the face of the column or concentrated load.

Explanation

Cantilever Sheet Piles:

• Best for shallow depths up to 6 meters.
• Relies entirely on the lateral passive resistance of the soil in front of the wall for stability.
• Larger depths cause extreme bending moments and deflections, requiring excessively heavy, thick, and costly pile sections

Explanation

• The horizontal movement of rails along the track is called rail creep,
• This is the longitudinal slip or forward movement of rails under traffic.
• Causes of Rail Creep
• Wheel impact and rolling loads from moving trains
• Starting and braking forces of trains

Explanation

• A geodetic survey is generally used for an area greater than 250 km² (or approximately 195.5 to 200 square miles),
• Where the shape and curvature of the Earth must be taken into account.

Additional information 

• Plane Surveying: Used for smaller areas under 250 km² where the Earth is treated as a flat surface.

Explanation

• A topographical map represents both natural and man-made features of an area.
• Natural features include rivers, trees, hills, valleys, and lakes.
• Man-made features include roads, buildings, bridges, and railways.

Explanation

• The joints of a truss should ideally experience purely concentrated point loads.
• In an ideal truss, loads are assumed to act at the joints (nodes).
• Truss members are subjected mainly to axial tension or compression