If car A is traveling at 50 km/hr at an angle of 10 degrees east of north and car B is traveling at 70 km/hr at an angle of 30 degrees south of east, what is the velocity of car A at seen by car B?
2007-01-31 05:06:56 · 1 answers · asked by GSU 1 in Science & Mathematics ➔ Physics
Let Vab be velocity of A wrt B
Let Vag be velocity of A wrt ground
Let Vbg be velocity of B wrt ground
Vab = Vag - Vab
Let 0 degrees be the east direction, and angles be measure counterclockwise
The angle of A is 100 degrees so
Vag = {50cos(100), 50sin(100)}
Vag = {-8.68, 49.24}
The angle of B is 330 degrees so
Vbg = {70cos(330), 70sin(330)}
Vbg = {60.62, -35}
Vag-Vbg = {-8.68-60.62, 49.24-(-35)}
Vab = {-69.3, 84.24}
This speed has magnitude
|Vab| = sqrt(69.3^2 + 84.24^2) = 109.08 km/h
And angle is
A = cos-1(-69.3/109.08) = 129 degrees which us 39 degrees west of north
2007-01-31 05:27:27 · answer #1 · answered by catarthur 6 · 0⤊ 0⤋