Corpus is a Latin word, which. means body. In financial usage, it. means a collection of bonds, stocks, or other holdings, which. form the principal1 of a trust fund. The concept of corpus is closely linked to. the concept of trust.
Physical changes occur when objects or substances undergo a change that does not change their chemical composition. This contrasts with the concept of chemical change in which the composition of a substance changes or one or more substances combine or break up to form new substances. In general a physical change is reversible using physical means.
A physical change is one where no new substance is made, but the substances we already had get reorganised. For example. when water boils, the steam is still the same molecule, water, just reorganised. The steel of your bike contains iron, which becomes iron oxide [which is rust]. It has reacted with oxygen in the air. Water in the air makes this happen more easily which is why you should keep your bike dry, or at least keep your bike painted well so that the iron/steel doesn't come in contact with air. The iron and oxygen were separate at the beginning, and are bonded together into a new substance at the end, so that tells us that this is a chemical change.