XX Question 3, the same XXXXXXXXX XX XXXXXXX as question 2. In XXXX case, XXX XXXXXXXX density, X, XX the XXXXXX XXX unit XXXXXX, or in other XXXXX density multiplied by g. You can thus directly use XXX XXXXXXXX P=γh, XXX i XXXXX used P=XXXand later XXXXXXXXX ρgto γ.