71. Pick up the incorrect statement from the following. On highways circular curves may be

A. simple curves

B. compound curves

C. reverse curves

D. vertical curves

72. The ideal shape of a transition curve, is

A. clothoid

B. cubic spiral

C. cubic parabola

D. lamniscate

73. The difference in gradients after full super-elevation and the initial alignment of a road, is known as

A. ruling gradient

B. rising gradient

C. compensated gradient

D. differential gradient

74. If x% is the gradient of an alignment and y% is the gradient after proper superelevation along a curved portion of a highway, the differential grade along the curve, is

A. (x + y)%

B. (x ?y)%

C. (y ? x)%

D. (x x y)%

75. If the rate of change of the super-elevation along a curved portion of a 7 metre wide road is 1 in 150 and the maximum super-elevation allowed is 1 in 15, the maximum length of the transition curve to be provided at either end, is

A. 65 m

B. 70 m

C. 75 in

D. 80 m

76. An ideal vertical curve is

A. true spiral

B. cubic spiral

C. cubic parabala

D. none of these.

77. In an ideal transition curve, the radius of curvature

A. is constant

B. at any point is directly proportional to its distance from the point of commencement.

C. is inversely proportional to the radius of main curve

D. is inversely proportional to the radius of main curve

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