An airplane maintains a speed of 633 km/h relative to the air it is flying throu
ID: 3140208 • Letter: A
Question
An airplane maintains a speed of 633 km/h relative to the air it is flying through as it makes a trip to a city 738 km away to the north.(a) What time interval is required for the trip if the plane flies through a headwind blowing at 35.7 km/h toward the south?
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(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 35.7 km/h to the east relative to the ground?
____________h??????
Explanation / Answer
a) If the plane's relative speed is 651, then it means that the sum of its actual speed and the wind speed = 651 If actual speed is V, then, V + 36 = 651 V = 615 Since we don't have any information about the air drag, we can ignore it and calculate the time taken by just using the plane's actual speed... So, time taken = 724/615 = 1.18 hours b) In this case, since the wind is blowing in the same direction as the plane, the relative speed = difference of their actual speeds. V - 36 = 651 V = 687 Time taken = 724/687 = 1.05 hours c) In this case, since the wind is blowing perpendicular to the direction of the plane, there is no component of wind velocity vector relative to the plane's velocity... as a result, the plane's speed is same as its relative speed to the wind. time taken = 724/651 = 1.11 hours