# Finding Angular Velocity

## Homework Statement

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?

## Homework Equations

Where were studying center of mass and Moment of inertia.

## The Attempt at a Solution

No idea, how to approach this question, Aircraft is flying straight, will there even by any angular velocity?

ehild
Homework Helper
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

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

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:
ehild
Homework Helper
Do not mix units. Convert the speed of the aircraft to m/s.

ehild