# Finding Angular Velocity

1. Nov 26, 2011

### haxan7

1. The problem statement, all variables and given/known data
An aircraft passes directly over you with a speed of 900 km/h at an altitude of 10,000 m. What is the angular velocity of the aircraft (relative to you) when directly overhead? Three minutes later?

2. Relevant equations
Where were studying center of mass and Moment of inertia.

3. The attempt at a solution
No idea, how to approach this question, Aircraft is flying straight, will there even by any angular velocity?

2. Nov 26, 2011

### ehild

Draw a straight line from your eye to the aircraft. It changes direction as the aircraft flies over you, does not it? The line encloses an angle alpha with the vertical. Find the expression for this angle in terms of time. The angular velocity is the time derivative of the angle.

ehild

3. Nov 26, 2011

### haxan7

Speed = 900km/hour
tan(α)=900t/10000
α=arctan(900t/10000)

Derivative is 900/(10000+81 t^2)
If i put t = 0 and t = 3/60, will i get the correct answer? I dont think so, Help me.

Last edited: Nov 26, 2011
4. Nov 26, 2011

### ehild

Do not mix units. Convert the speed of the aircraft to m/s.

ehild

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