Q A lamina is in the shape of an isosceles trapezium. The two parallel sides are 5 m apart and their lengths are 3 m and  2 m . The distance of the centre of mass of the trapezium form the longer of the parallel sides is :


(a) 8/3 m        (b) 8/15 m         (c) 6 m             (d) 7/3 m 

Dear student

Y coordinate of centre of mass is ycm=A1y1+A2y2+A3y3A1+A2+A3Area of triangle ABC(A1)=Area of triangle DEF(A2)=12×12×5=54m2Area of rectangle ACDE (A3) is =2×5=10m2y cordinate of centre of mass of a triangle is =h3  (h is the of perpendicular dropped from one of its vertex on the opposite base)h=5my1=y2=53 and y3=52ycm=A1y1+A2y2+A3y3A1+A2+A3=54×53+54×53+10×5254+54 +10  =256+25104+10=256+2552+10multiplying numerator and the denometor by 617515+60=17575=73mRegards

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