COURSEWORK IN VECTOR CALCULUS

Coursework instructions Answer all parts of the question below in no more than 5 A4 sides. Submit a scanned copy of your report via Learn by 12 noon on Thursday the 19th of March. Submit only your own work.

**Question 1**

Consider R to be a sphere centred at the origin with boundary ρ = 2 in spherical coordinates. Within it there is a spherical compartment that is vacuum with boundary ρ = 1. You may assume that the vacuum has density zero. The density of the materials inside the sphere where 1 ≤ ρ ≤ 2 is equal to 1 for z ≥ 0 and 2 otherwise.

(a) Compute the z coordinate of the centre of mass of R.

(b) An X-ray source is positioned at a known point with spherical coordinates (ρs,φs,θs) (away from the sphere) emitting a beam of intensity Iin aligned to a vector that’s normal