A mountain range 4 km high is in (Airy) isostatic equilibrium.
i) How deep is the root of the mountain for a crustal density of 2.8x103 kg/m3 and a mantle density of 3.3x103 kg/m3.
ii) During a period of erosion, 2 km of crustal material is removed from the mountain. When the new isostatic equilibrium is achieved how high are the mountains?

First answer marked as brainiest which is the correct equation describing the first law of thermodynamics? a) when the internal energy of a system changes, it equals the amount of heat added plus the work done. b) when work is done by the piston, it is equal to the heat added plus the change in internal energy of the system. c) when heat is added to the system, it is equal to the amount of work done by the piston plus the change in internal energy of the system.