why does a single raindrop process a relatively great power to erode soil?

Answer 1

when a rain drop falls it absorbs minute quantities of minerals from the soil and it will deposit those mionerals in another place further down the slope (this works only on slopes) when the water drop evaporates or runs into a river. The amount that it absorbs and moves is negligible on its own but over time and thousands & millions of raindrops can erode a landscape fairly quickly depending on how hard the ground material is. Rock will take thousands of yeras whereas top soil on a slope can disappear in a singl;e day if their is sufficient rainfall

Answer 2

Just as a single penny can add up to a whole dollar. Then a hundred! Even... ?
Or, just as a single drop, when added to others, fills a bucket. Each raindrop, falling at 180 MPH can chip out a tiny piece of dirt. Thousands chisel out thousands of bits and wash them away, turning the streams brown or red or whatever the color of the suspended soil.

Answer 3

Leland is absolutely correct. Rain drop impact in a years time has the explosive equiv. of 1 million tons of TNT.
Each drop on contact with exposed soil, will dis-lodge the soil particles..That is why ground cover is important.

Answer 4

A "single" raindrop doesn't. Who told you that it did?

Rain-saturated soil can slip if it's on a slope, resulting in a mud slide. Rain in general can carry bare soil with it as it runs downhill, causing erosion over time. Ground cover (plants) protect the soil from this effect.