hello.. i do not understand this question was hoping that someone could guide me through this..

A flat circular disc, of radius R, can be modelled as a thin disc of negligible thickness.

It has a surface mass density function given by f(r,0) = k(1-r^2/R^2),

where k is the surface density at the centre and r is the distance from the centre of the disc.

Using area integral in plane polar coordinates, calculate the total mass of the disc, in kg, when R = 0.15m and k = 12 kg/m^2