An airplane maintains a speed of 645 km/h relative to the air it is flying throu
ID: 1278223 • Letter: A
Question
An airplane maintains a speed of 645 km/h relative to the air it is flying through as it makes a trip to a city 745 km away to the north. (Assume north is the positive y-directionand east is the positive x-direction.)
(a) What time interval is required for the trip if the plane flies through a headwind blowing at 32.1 km/h toward the south?
?h
(b) What time interval is required if there is a tailwind with the same speed?
?h
(c) What time interval is required if there is a crosswind blowing at 32.1 km/h to the east relative to the ground?
? h
Explanation / Answer
VpE = VpW + VwE = 645j - 32.1 j = 612.9j
t = 745/612.9 = 1.22 hr
-----------------
VpE = VpW + VwE = 645j + 32.1 j = 677.1j
t = 745/677.1 = 1.1 hr
--------------
645*costheta = 32.1=======> theta = 87.1
VpE = 645*sin87.1 = 644.2
t = 745/644.2 = 1.16 hr