Question

From the uniform disc of radius 4 R two small discs of radius R are cut (as shown). The centre of mass of the new structure will be : (Centre of lower circular cavity on x-axis and centre of upper circular cavity *** on y-axis )

Answer 1

Correct option: (D)

Explanation:

Centre of mass of circular disc of radius 4R = (0, 0)

Centre of mass of upper disc = (0, 3R)

Centre of mass of lower disc = (3R, 0)

Let M be mass of complete disc and then the mass of cut out disc are M/16

Hence, centre of mass of new structure is given by

similarly for y

Position vector of C.M.