Earth is mot exactly a sphere - spinning on the axis makes it a little larger around the equator than at the poles. Thus, at the poles the mass in question is slightly closer to the center of the earth. Since gravity acts as though attraction is at the centers of mass, weight would be slightly higher at the poles, less at the equator. Same thing happens on mountain tops vs deep valleys.
As far as rockets are concerned, it is the mass of the burning gasses ejected out the nozzle that causes the motion. "For every action, there is an opposite reaction." Gasses eject in one direction driving the rocket in the other. No need for an atmosphere to push against.
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Today's Featured Article - Third Brush Generators - by Chris Pratt. While I love straightening sheet metal, cleaning, and painting old tractors, I use every excuse to avoid working on the on the electrics. I find the whole process sheer mystery. I have picked up and attempted to read every auto and farm electrics book with no improvement in the situation. They all seem to start with a chapter entitled "Theory of Electricity". After a few paragraphs I usually close the book and go back to banging out dents. A good friend and I were recently discussing our tractor electrical systems when he stated "I figure it all comes back to applying Ohms Law". At this point
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