Please assist

1. A semi-circular wire is formed with the help of a wire of length {. Find the position of the center of mass of the semicircular wire from the point \"O\" as shown in the figure \"O\" 2. Prove that the Moment of Inertia of a solid sphere of mass M and radius R, about its L s S ot 2 diameter as the axis of rotation is given as 5 MRZ. 3. Find the center of mass (X, cp) of the pile of bricks stacked as shown in the figure below. The dimensions of the bricks (length, width) is given as (I, w) !