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.
Best Answer: There are various causes of both types. Mechanical weathering is associated with a change in size of particle, or a breaking apart of the rock, ice wedging, wave action, tumbling in water, wind abrasion, could all cause this.hemical weathering is caused by changes in a rock's chemical composition. For example, in a limestone cave, when Hydrocloric acid or acid rain comes in contact with the stalagmites and stalacatites, it will break them down. Rusting is another example of chemical weathering. The process is called Oxidation.