1. Oct 7, 2009

### samxel

1. The problem statement, all variables and given/known data

A radar station, located at the origin of xz plane, as shown in the figure, detects an airplane coming straight at the station from the east. At first observation (point A), the position of the airplane relative to the origin is R_vec_A. The position vector R_vec_A has a magnitude of 360m and is located at exactly 40 degrees above the horizon. The airplane is tracked for another 123 degrees in the vertical east-west plane for 5.0s, until it has passed directly over the station and reached point B. The position of point B relative to the origin is R_vec_B (the magnitude of R_vec_B is 880 m).

find the ordered pair (x,z) for components of the vector R(AB), which I am suppose to be able to find by R(AB) = R(B) - R(A).

PICTURE OF PROBLEM

http://i37.tinypic.com/2pzfml1.jpg

2. Relevant equations

3. The attempt at a solution

Vector A:
cos 40 = x/360; x = 276
sin 40 degrees = y/360; y = 231
RAx, RAz= (275.775 , 231.40)

Vector B:
angle (123+40=163; 180-163=17 degrees)
cos 17 = x/880; x =-841.55
sin 17 = y/880; y = 257.29
RBx,RBz= (-841.55, 257.29)

RBA = Vector B - Vector A = (-841.55, 257.29) - (275.775 , 231.40) = (-116.84,25.89)

MY ANSWER IS NOT RIGHT. I must be missing something but i cant see it.

2. Oct 7, 2009

### rl.bhat

RBA = Vector B - Vector A = (-841.55, 257.29) - (275.775 , 231.40) = (-116.84,25.89)
Check this value.

3. Oct 7, 2009

### samxel

oh damn! that was it . stupid calculator ;)

thanks a lot. Been doing work all day my mind is not working right, right now.