ASTRON 2B03 Lecture Notes - Lecture 4: Skateboarding, Thought Experiment, Spacecraft
6 Dec 2017
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Distance the meter was defined as the length of a particular rod of metal. Distance to the sun ~ 100,000,000,000 meters i. e 1011 m. Distance to the nearest galaxy ~ 2 x 1022 m. Size of atom ~ 0. 0000000001 meters i. e 10-10 m. *1960, the meter was redefined as equal to 1,650,763. 73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum. A second is a measure of time. Defined as a certain number of vibrations of a cesium atom. Your age ~600,000,000 s i. e 6 x 108 s. Age of the universe ~ 4 x 1017 s. Mass is a (cid:373)easure of the (cid:862)i(cid:374)ertia(cid:863) of a(cid:374) o(cid:271)je(cid:272)t. The greater the mass, the harder it is to accelerate it. Speed is the distance travelled in a second. The speed of light is 300,000,000 m/s (use the symbol c) The distance travelled is just the speed multiplied by the time travelled.
