Aeroplane A flies due east at 400 km h⁻¹. Passengers in A observe aeroplane B moving perpendicular to A's direction. B actually moves 30° north of east. Which vector gives B's velocity?

Question

G1 Physics · Accepted Answer

For B relative to A to be perpendicular to east, its east component must be 400. If B makes 30° north of east, Vᵦcos30°=400. Therefore its north component is Vᵦsin30°=400/√3. Option A.