Recent content by gnaman

Lots of economic modeling does require Calculus of varying degrees. Some of these, like calculating slopes, I am able to do without problems. But what does it say about our educational system when I was able to get a BS in Economics from one of the top 20 public universities in the US, without...

Fair enough. I think I may just have to push this problem out of my head. I can multiply 4 and 5 digit numbers quickly in my head, but for some reason have been unable to grasp Calculus. If I had had a Calculus teacher like phyzguy, who explained Calculus through tangible real-world examples, I...

Do I believe it? I should. It's Newton after all right? Do I understand it? Not exactly. I feared when I wrote this I would have to take a couple courses in calculus to fully understand. Thanks to peroK for the link to these calculations. Alas, the math is far above me and I may have to resign...

The more I think about my crude drawing above, maybe my mistake is simplifying the Earth to 2d instead of 3d? Is this my error?

Aha! Now I am getting closer to understanding, though I hesitate to say I am thoroughly convinced. Are we sure that 1/4 or less of a sphere's mass is within 1 radius of a position on its surface? Or is this purely due to Earth's increasing density with depth? Please see my embarrassingly...

Thanks for your response. I certainly agree that, in my example using the 100km sphere, that this sphere represents only a fraction of the Earth's mass. Maybe a better example would be to envision standing on the North Pole. Assuming a perfect sphere, there would be equal matter above the...

Newton showed that F=G(m1m2)/r2 When calculating the force of gravity on the surface of the Earth, why do we use the radius of the Earth for our r value? Of course, the above Newtonian equation suggests we should, but it seems rather counter-intuitive. I must admit to not having taken a...