Are lichen growing in rocks mechanical or chemical weathering?

When solid surfaces slide over each other the kind of friction that occurs is called friction

Anthropology is the study of the effects of disease on the body, while forensic anthropology studies the disease of crime a.) true b.) false

Aspring has a relaxed length of 33 cm (0.33 m) and its spring stiffness is 6 n/m. you glue a 76 gram block (0.076 kg) to the top of the spring, and push the block down, compressing the spring so its total length is 15 cm. you make sure the block is at rest, then at time t=0 you quickly move your hand away. the block begins to move upward, because the upward force on the block by the spring is greater than the downward force on the block by the earth. calculate y vs. time for the block during a 0.09-second interval after you release the block, by applying the momentum principle in three steps each of 0.03-second duration.