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.
Biological weathering occurs when something living interacts with the weathering processes, causing the rock to break down. Biological weathering can be considered a type of physical weathering. Sometimes biological weathering is referred to as the third type of weathering.