New center of mass is given by:
\(x_{com} = \frac{m_1x_1 - m_2x_2}{m_1 - m_2}\)
where,
m1 is mass of original disc
m2 is mass of removed disc
x1 is center of mass position of original disc
x2 is center of mass position of removed disc
If mass per unit area=m then,
mass of original disc = m × π × (28 × 10−2)2
mass of removed disc = m × π × (21 × 10−2)2
Center of mass shifts by 9 cm.
