183_notes:examples:relativemotion

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A Boeing 747 leaves the Detroit airport intending to head due west. The plane is experiencing a strong crosswind that is blowing toward the south, which has a wind speed of 10.0 m/s. Determine the speed of plane relative to the ground and the direction its compass should read if the pilot intends to fly due west at top speed.

You need to determine the speed and direction of the plane using information given and any information that you can collect or assume.

Facts

  • The pilot intends to fly due west.
  • The plane experiences a crosswind with a speed of 10.0 $\dfrac{m}{s}$, which is directed due south.

Lacking

  • The top speed of a Boeing 747 is unknown, but can be found online (920 $\dfrac{km}{h}$ or 255 $dfrac{m}{s}$).

Approximations & Assumptions

  • The windspeed is measured relative to the ground.
  • The plane's airspeed is measured relative to the air.
  • At top speed, the plane is flying level with ground.
  • The plane has a constant velocity over the interval you care about it.

Representations

  • The velocities of the plane relative to the air, the air relative to the ground, and the plane relative to the ground are represented in the following diagram.

Add vector addition diagram

  • The relative velocity equation for three objects is: $\vec{v}_{A/C} = \vec{v}_{A/B} + \vec{v}_{B/C}$ where $\vec{v}_{A/C}$ is the velocity of object A with respect to object C, etc.
  • 183_notes/examples/relativemotion.1405045743.txt.gz
  • Last modified: 2014/07/11 02:29
  • by caballero