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Home >All Categories > Science & Mathematics >Mathematics >Open Question bookie Member since:August 15, 2006Total points:103 (Level 1)Scientists can determine the age of ancient objects by a method called radiocarbon dating. The bombardment of the upper atmosphere by cosmic rays converts nitrogen to a radioactive isotope of carbon, 14C, with a half-life of about 5730 years. Vegetation absorbs carbon dioxide through the atmosphere and animal life assimilates 14C through food chains. When a plant or animal dies, it stops replacing its carbon and the amount of 14C begins to decrease through radioactive decay. Therefore, the level of radioactivity must also decay exponentially. A parchment fragment was discovered that had about 64% as much 14C radioactivity as does plant material on Earth today. Estimate the age of the parchment.Answer Question

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Home >All Categories > Science & Mathematics >Engineering >Open Question Joseph Barnes Member since:April 04, 2011Total points:95 (Level 1)I am in a engineering class and some of the kids in this class took home 3rd and 4th in state in stead of 1st because they could not put center lines in place on certian features of the objects. How would you project a center line from an adjacent view in autodask inventor 2009?Answer Question

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If I am only given one of the masses of the objects and acceleration and asked to find the mass of the other object. How do I know if object 1 is gonna go down the ramp lifting object 2 or object 2 going down lifting object 1 up the ramp?

object 1: on ramp
object 2: hanging on pulley

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I often hear that larger mirrors are used in telescopes in order to collect more light, in order to create brighter images, but this doesn't fit with observations of non-telescopic mirrors. Objects don't look brighter in bigger mirrors than smaller ones, so why would bigger mirrors in telescopes create brighter images?

Also, why is it that refracting telescopes have fallen out of favor and instead most advanced telescopes today are reflecting, but for camera lenses refracting lenses are preferred to reflecting ones?

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