TS EAMCET 10-Sep-2020 Shift 1 Solved Paper

Let mass per unit area of the disc =m
Total mass of disc, M=πR2m
Mass of the scooped out portion of the disc,
M′=πr2m
For small objects, centre of gravity and centre of mass are at same position.
We take the centre O of the disc as the origin. The masses M and M′ can be supposed to be concentrated at the centres of the disc and scooped out portion respectively. The mass M′ of the removed portion is taken negative.The x -coordinate of the centre of mass of the remaining portion of the disc will be
⇒xCM=−lcm
Hence, distance of centre of gravity of the resulting flat body from the centre of the original disc will be 1cm left side.