another vectors quetion! pleaaase help!?

Question

At 13:30 helicopter B makes an emergency landing at (168i + 49j) km, A immediately changes direction (from ( 49i and 144j ) km and flies at 120 km/h in a straight line to B. Determine the time when A reaches B

Velocity of A=72i+96j
Velocity of B+ 0i+ 0j

Answer 1

Well, you're covering 168-49 kilometers in the i direction and 144-49 kilometers in the j direction. (Sign doesn't matter in this problem, because we're about to square things.)

Square those, and take the square root of their sum, and you'll have computed the distance actually traveled. Divide by 120 and you'll know how many hours elapsed. Add to 13:30 and you'll know the time of arrival.