What is an ellipse? What does it mean when an ellipse is in a perfect circle? What causes a black hole?
2007-02-01 17:29:33 · 2 answers · asked by Sally 2 in Science & Mathematics ➔ Physics
Ellipse is a geometrical figure with two focus and two directrices. Directrices are simply lines and focus is a point. The eccentricity of an ellipse is less then one. Eccentricity is the ration of distance of a point lying on the ellpse from focus to the distance from corresponding directrix. An ellipse is converted to a perfect circle if its eccentricity becomes zero. A black hole is caused due to the shrinking of a planet so that its radius becomes nearly zero and as a result gravitational acceleration and escape velocty increases to such extent that nothing even not the light can escape the planet.Hence it is called a black hole.
2007-02-01 18:57:55 · answer #1 · answered by Tariq M 3 · 0⤊ 0⤋
http://en.wikipedia.org/wiki/Ellipse
2007-02-01 19:14:21 · answer #2 · answered by gp4rts 7 · 0⤊ 0⤋