physics
Like Frogs in a Well
May 23, 2013
Simple visualizations (such as the one shown in the figure) of this curvature, typically appeal to a 2D fabric of space curved into a third dimension by the presence of a mass such as the earth. This curvature creates a three dimensional "well" into which other masses fall, thus resulting in what we perceive as gravity.
Why parabolic reflectors?
Mar 26, 2012
At school, we are taught that parallel rays incident on the mirror, after reflection, pass through the focus of the mirror, and that irrespective of the position of these parallel rays, the position of the focus does not change. But that is not quite true. It is just an approximation.
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