Vectors p and q have magnitudes ∣p∣=10 units and ∣q∣=15 units. The angle between them, when they are placed with a common tail, is 60∘.
(i) Calculate the magnitude of the resultant vector R=p+q.
(ii) Find the angle between R and p.
(iii) Suppose instead that q is placed first and p second while keeping the same 60∘ between them. Show numerically that the magnitude of the resultant remains the same although the angle it makes with q changes correspondingly.