What is the definition for chemical change

In the 1980's, congress authorized the u.s. department of energy to build the wipp facility in the chicuahuan desert in new mexico. what is the purpose of wipp?

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

What is the measure of a change in an objects velocity?