Question

Angle between two vectors of magnitude 12 and 18 units when their resultant is 24 units is

Answer 1

Answer:

Let the vectors be A=12, B =18

let sum be, S = 24

S² = A² + B² + 2ABcosθ

24² = 12² + 18² + 2*12*18*cosθ

576 = 144 + 324 + 432cosθ

(576-144-324)/432 = cosθ

cosθ = 1/4

θ = cos⁻¹(1/4) ≈ 75.5°