551. The probability that the load on a scaffolding will exceed the design load of 3 tonnes is 0.15. At the same time, the probability that the strength of the scaffolding will be more than 3 tonnes is 0.85. The probability that the scaffolding will fail is
552. The dry density of a soil is 1.5 g/cc. If the saturation water content were 50%, then its saturated density and submerged density would, respectively, be
553. Consider the following soil parameters and conditions :
1. Drainage conditions
2. Thickness of layer
3. Initial void ratio
4. Over-burden pressure
The magnitude of settlement is influenced by,
554. A concentrated load acting on the surface of a soil produces a stress of 19.1 kPa at a depth of 1 m below it. Using Boussinesq's expression, the stress at 2 m depth is
555. Consider the following statements :
Seasoning of timber results is
1. increased strength
2. increased durability.
3. reduced resilience.
Of these statements :
556. Gypsum is added to Portland cement during its manufacture so that it may
557. If the velocity potential φ = 4 xy, what are the x and y components of velocity at the point(1, 4) ?
558. Unit cost of any item of work can be found by using
559. Which one of the following different types of submerged soils is susceptible to liquefaction under earthquake shocks ?
560. In the given figure, σ1 and the σ2 and maximum and minimum principal stresses. In order that the resultant stress on the plane AB is the value of θ should be
561. Eutrophication of water bodies is caused by the
562. For laminar flow through a circular tube, the average velocity at a section is
563. In the figure shows, the effective pressure at C is given by (symbols have the usual meanings)
564. Consider the following assumptions :
1. Failure occurs on a plane surface.
2. Wall is smooth but not necessarily vertical.
3. Failure wedge is a rigid body.
Coulomb's theory of earth pressure is based on assumptions
565. A 2-metre diameter water pipe is required to withstand a 200 meter head of water. Assuming the limiting tensile stress for the pipe material to be 200 kg/cm2, the minimum thickness of the material of the pipe to be used will have to be
566. In the preliminary treatment of wastewater, skimming tanks are often included in the treatment scheme. Various features of skimming tanks are that these :
1. can remove general floating matter.
2. can remove oily and greasy matter.
3. have detention time of 30 min.
4. employ compressed air blown through diffusers.
Which of these statements are correct ?
567. Consider the following statements :
1. A dummy activity is artificially introduced in a network when necessary.
2. A dummy activity consumes some time.
3. A dummy activity is represented by a dotted arrow.
4. A dummy activity must necessarily be introduced in every network. Which of the above statements are correct ?
568. Consider the following stages in the manufacturing of bricks :
1. Weathering
2. Moulding
3. Tempering
The correct sequence of these stages in the manufacturing of the bricks, is
569. What is the predominating coagulation mechanism for raw water having high turbidity and high alkalinity?
570. The momentum correction factor (β) is used to account for
571. Where is d'Alembert's principle employed ?
572. The hoop stress in a dome subjected to uniformly distributed load
573. A commonly used handpump is the
574. What is the ratio of the forces in the members AB, BE and AE of the pin-joined truss shown in the figure?
575. A sewer, 1000 mm in diameter is laid at a slope to obtain a velocity of 0.8 m/s when running full. Assuming Manning's n as constant, what is the velocity in this sewer if it is running half full.