Car A is 200 m west of an intersection and moves east at 20 m/s. Car B is 400 m north and moves south at 20 m/s. If their minimum separation is 20√N m, find N.

Question

G1 Physics · Accepted Answer

Take relative initial position r⃗₀=(200,−400) and relative velocity v⃗=(−20,20). d_min=|200×20−(−400)(−20)|/(20√2)=4000/(20√2)=100√2=20√50 m. Hence N=50.