In some areas of the world, like california and japan, earthquakes are a common occurrence. how can this best be explained? a) the strong ocean currents are undermining both areas causing earthquakes. b) both area are subjected to strong ocean wind and waves that causes earthquakes. c) both areas are located near the edge of the pacific ocean, the unstable sand causes earthquakes. d) both areas are on the boundary of active plate margins, the motion of the plates causes earthquakes.

Suppose that two tanks, 1 and 2, each with a large opening at the top, contain different liquids. a small hole is made in the side of each tank at the same depth 1.57 m below the liquid surface, but the hole in tank 2 has 2.49 times the cross-sectional area of the hole in tank 1. (a) what is the ratio ρ1/ρ2 of the densities of the liquids if the mass flow rate is the same for the two holes? (b) what is the ratio rv1/rv2 of the volume flow rates from the two tanks? (c) at one instant, the liquid in tank 1 is 14.9 cm above the hole. if the tanks are to have equal volume flow rates, what height above the hole must the liquid in tank 2 be just then?