Consider a circular disc of radius 20 cm with centre located at the origin. A circular hole of radius 5 cm…

Consider a circular disc of radius 20 cm with centre located at the origin. A circular hole of radius 5 cm is cut from this disc in such a way that the edge of the hole touches the edge of the disc. The distance of centre of mass of residual or remaining disc from the origin will be
  1. 2.0 cm
  2. 1.5 cm
  3. 1.0 cm
  4. 0.5 cm

Solution


$\text { mass of disc }=\mathrm{m}$
$\text { mass of cut part }=\frac{m}{16}$
$X_{c o m}=\frac{m \times 0-\frac{m}{16} \times 15}{m-\frac{m}{16}}$
$=1 \mathrm{~cm}.$

Asked in: JEE Main 2025 (23 Jan Shift 1)

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