Qualification > Math
additional maths...igcse...o-level....
vaan:
hey ppl...put ur add.math question here...n hope dat me...or some1 else 'll help..... ;) :)
sameer210394:
--- Quote from: vaan on November 09, 2009, 12:03:21 pm ---hey ppl...put ur add.math question here...n hope dat me...or some1 else 'll help..... ;) :)
--- End quote ---
A plane flies due north from A to B a distance of 1000 km, in a time of 2 hrs. During this time a steady wind, with speed of 150 km/h, is blowing from the south-east. Find the direction in which the plane must be headed.
i hav solved this question, but need more practice in it, so du u have any note for such type of questions, and wat do u call this type of questions, which chapter are these questions frm ???
slvri:
--- Quote from: sameer210394 on November 09, 2009, 12:51:53 pm ---
A plane flies due north from A to B a distance of 1000 km, in a time of 2 hrs. During this time a steady wind, with speed of 150 km/h, is blowing from the south-east. Find the direction in which the plane must be headed.
i hav solved this question, but need more practice in it, so du u have any note for such type of questions, and wat do u call this type of questions, which chapter are these questions frm ???
--- End quote ---
these are relative velocity questions. i know theyre hard, theyre real b*tches...........anyways
VP=1000/2=500 kmh-1
VW=150 kmh-1
the direction the plane must be steered in is of VP/W
the relative velocity equation is VP=VP/W+VW
refer to diagram attached
theta is the angle that the plane must be steered on
using the cosine rule
cos45=(5002+1502-Vp/w2)/2(500)(150)
Vp/w=407.96kmh-1
using the sine rule
150/sin theta=407.96/sin45
theta=15.1degrees
bearing is 015.1degrees
sorry for the sh*tty diagram but my drawing sucks in Paint
hope this helped
Ghost Of Highbury:
hey slvri, just 1 doubt, isnt 500km/h the velocity of plane relative to wind? because after the wind is blown it moves north rite?
sameer210394:
--- Quote from: A@di on November 09, 2009, 02:34:26 pm ---hey slvri, just 1 doubt, isnt 500km/h the velocity of plane relative to wind? because after the wind is blown it moves north rite?
--- End quote ---
arrey the answer is right. read the quest carefully n u will c that the plane travels 1000 km, and while traveling this distance the wind is also blowing...
therefore there 2 forces acting, 1 of the plane and one of the wind to travel the 1000 km distance.
Now this results in a vector where the total velocity ( 1000/2 = 500 Km/h ) equals the velocity of plane in still air and the velocity of wind.
thus: this form a triangle as drawn by slrvi where AB is 500Km/h.
i hope this is clear.
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