When sand is picked up by the wind and breaks down bigger rock why is this a physical change?

The position of a crate sliding down a ramp is given by x=(0.05t^3) m, y=(1.7t^2) m, z=(6−0.85t^5/2) m, where t is in seconds. (a) determine the magnitude of the crate's velocity when t = 2 s. (b) determine the magnitude of the crate's acceleration when t = 2 s.

Diamond will scratch quartz. true or false

Give me a example of a decomposer. explain what would happen if decomposers were absent from a forest ecosystem