(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Heading straight toward the summit of Pikes Peak, an airplane of mass 12,000 kg flies over the plains of Kansas at nearly constant altitude 4.30 km with constant velocity 175 m/s west. a) What is the airplane's vector angular momentum relative to a wheat farmer on the ground directly below the airplane? b) Does this value change as the airplane continues its motion along a straight line?

2. Relevant equations

mag. of angular momentum = position*mass*velocity*angle between

3. The attempt at a solution

The answer to part a) is (-9.03 x 10^9 kg x m^2/s) j, which I have no problem with. But the answer to part b) is "No, L = |r||p|sin(Θ) = mv(rsinΘ), and r*sinΘ is the altitude of the plane. Therefore, L = constant as the plane moves in level flight with constant velocity."

But the problem asks for the plane's angular momentum relative to the wheat farmer. So if the plane keeps on moving west, wouldn't r (the distance between the farmer and the plane) keep on increasing?

The only way the answer makes sense to me is if they're really asking for the angular momentum of the plane relative to the ground, not the wheat farmer, because then, the distance between the plane and the ground would be constant.

Any help would be great...

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# Homework Help: Semantics question about this angular momentum problem

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