In Section 11.2 we always assumed that the value of g was the same at all points on the body. This is ?not a good approximation if the dimensions of the body are great enough, because the value of g decreases with altitude. If this is taken into account, will the center of gravity of a long, vertical rod be above, below, or at its center of mass? Explain how this can be used to keep the long axis of an orbiting spacecraft pointed toward the earth. (This would be useful for a weather satellite that must always keep its camera lens trained on the earth.) The moon is not exactly spherical but is somewhat elongated. Explain why this same effect is responsible for keeping the same face of the moon pointed toward the earth at all times.
Geo 202 Unsustainable food production How is soil resources related to crops We consume: land/soil/ water/ energy/ mineral resources Soil forming processes 1. Parent rock: original composition 2. Relief and Landscape Factors 3. Climate 4. Biosphere 5. Time Soil loss= erosion: wind, water, bad agricultural/ construction practices, change in climate, deforestation It takes 1,000 years form an inch of soil. Soil conservation practices o Terracing o Strip-cropping o Crop rotation o Wind breakers Water use 37% of US water has been withdrawn 70% globally ½ of water used in irrigation is consumed NOT returned. Over pumping of ground water: uses a large amount of energy Climate changes will increase water issues with loss of Andes/ Himalayas, drought and lower water tables, & shifting of weather patterns Disappearance of glaciers will hurt other regions that rely on their yearly ice melt Mineral resources Critical nutrients: P, N, K o (K) Potash reserves: 100’s of years of reserves o (P) Phosphorus reserve: US has 25 -100 years of Phosphorus reserves o (N) Nitrogen reserves: “fixed” from the atmosphere/ the Haber- Bosch process/ Makes Ammonium nitrate when reacting with natural gas What is eat