232.  The displacement of a particle which moves along a straight line is given by S = 4t3 + 3t2 ? 10 where S is in meters and t is in seconds.The acceleration of the particle when its velocity is 18 m/sec, is
A. 15 m/sec2.
B. 20 m/sec2.
C. 25 ailsec2.
D. 30 m/sec2.

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233.  The ratio of the moment of inertia of a rectangle about its centroidal axis to the moment of inertia about its base, is
A. 1/4
B. ?
C. 3/4
D.2

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234.  The centre of gravity of a triangle is at the point where three
A. medians of the triangle meet
B. perpendicular bisectors of the sides of the triangle meet
C. bisectors of the angle of the triangle meet
D. none of these.

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