Driving on the 87 Octane yields 20 mpg so the driver is able to pass 200 miles for $31.00 dollars and the cost per mile will be $0.16. The example above is simplified but shows that even though the entry cost is lower and in the end, the gas will end up costing more.
Weathering of rocks is caused by chemical and mechanical means, and the types of weathering are therefore generally classified as chemical or mechanical (also known as physical).1  Slightly acidic rainwater can react with rock surfaces, dissolving them over time.ockhound. Weathering of rocks is caused by chemical and mechanical means, and the types of weathering are therefore generally classified as chemical or mechanical (also known as physical). 1  Slightly acidic rainwater can react with rock surfaces, dissolving them over time.
This is the result of weathering and can even break down into smaller pieces. Major Types of Weathering: 1  Mechanical (physical): is the disintegration of rock by physical processes and involves no change in chemical composition -- the rock is breaking down into smaller fragments by physical means. The predominant type of weathering in a dry climate results in angular type landscapes with sharp-breaking slopes. ( 2 e.g. Del Rio, West Texas, New Mexico, Arizona). 3  Ice Wedging -- water seeps into cracks in rocks and then when it freezes, the water expands and expansion of the water causes the rocks to break apart.