# Relative Velocity of a plane

a,The Speed Of an aircraft in still air is 300 km/h.
In a wind of speed 140 km/h, blowing from a bearing of 230, the aircraft flies due east. Find
i, the course set by the pilot
ii, the time taken for the aircraft to travel 100 km.

b,To a cyclist traveling due east at 18 km/h the wind appears to be blowing at 12 km/h from a bearing of 150. Find the true wind-speed and the direction from which the wind is blowing.

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nicksauce
Homework Helper
Where's your attempt at a solution?

how to draw a vector diagram ?? of the above problem?? I only have problem in that...

its all simple trigonometry .... after that... i need to know what will be the direction of Aircraft in still air? what does that mean? what will be the direction of of wind... how will we create a vector diagram...of it?

You should be able to draw 3 vectors, where one of them is the final speed and direction of the moving object(which you can find by vector addition).

tiny-tim
Homework Helper
how to draw a vector diagram ?? of the above problem?? I only have problem in that...
Hi Zoheb! Give them letters!

Call the plane P, the air A, and the ground G.

Then P - A = 300, and A - G = 140 @ 230º.

And you know that P - G is 90º.

Draw a triangle with an arrow on each side, so that the arrow along P - A goes the same way as the arrow along A - G (in other words, it doesn't meet it head-on).

Does that make sense? … what will be the direction of Aircraft in still air?
Not relevant … in still air, it would go at 300 in any direction … they're simply telling you how powerful the aircraft is.