Physics Physics Physics short question? help ?????? thanks?

Question

What is the velocity of car 2 relative to car 1? Help Physics question??Thanks :)?
Two cars approach a street corner at right angles to each other. Car 1 travels at a speed relative to Earth v1E = 27 km/h, and car 2 at v2E = 51 km/h.

(a). What is the relative velocity of car 1 as seen by car 2?
57.71 km/h; 62.103° (west of north)

(b). What is the velocity of car 2 relative to car 1?
........km/h;.......° (south of east)


Please help me to do this Physics Question? i got the first questions and it turns out to be right..but how do i get the velocity of car 2 relative to car 1?????????? please show the work also ..Thanks :)

Answer 1

The first answer has the idea. (a) asks for v1-v2, and (b) asks for v2-v1, which is the same vector except pointing in the opposite direction. So the magnitude is the same and the angle is 180 deg away from 62.103. That would be 62.103 deg east of south (opposite of west of north). But since you are asked for the south of east angle, subtract 62.103 from 90 deg for the answer.
I'm a little confused by your labeling of the variables v1E and v2E, which I'd take to mean they're both traveling east, which they're not. From your answer, with its 51 km/hr westward component, it seems car 1 goes north and car 2 goes east, so you'd have v1N and v2E. Is that correct?

Answer 2

It is the same thing as problem (a), but worded differently.