A 12.0 kg object is stationary on a surface that is inclined 30.0° relative to the horizontal. The coefficient of friction is 0.65. Use a free body diagram to determine the magnitude of the force of static friction on the block.

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other

One answer could be erosion

If you're looking for an even spread of clay, silt and sand, add a considerable amount of sand and some clay until the 3 even out". soil texture triangle. silty clay loam soil is approximately 20 percent or less sand, 25 to 40 percent clay, and 40 to 70 percent silt.