Describe pyroclastic flows and explain why they are capable of traveling great distances
What will be an ideal response?
Pyroclastic flows consist of hot gases infused with incandescent ash and larger lava fragments. Also referred to as nuée ardentes, these fiery flows are capable of racing down steep volcanic slopes at speeds that can exceed 100 kilometers per hour. Pyroclastic flows are propelled by the force of gravity and tend to move in a manner similar to snow avalanches. They are mobilized by expanding volcanic gases released from the lava fragments and by the expansion of heated air that is overtaken and trapped in the moving front. These gases reduce friction between ash and pumice fragments, which gravity propels downslope in a nearly frictionless environment. This accounts for the reason some pyroclastic flow deposits are found many miles from their source.
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Name the three vector data formats that Esri has developed since the 1980s.
What will be an ideal response?
According to the impulse-momentum equation Ft = change in (mv), a bungee jumper in fall has momentum which is reduced by the force F exerted by the bungee cord. If m is the mass of the jumper, then v in the equation is the speed of the
A) jumper. B) cord. C) both A and B D) none of the above
What economic pursuit drew the Basques from their homeland in the Pyrenees Mountains in Europe to migrate to rural Nevada and Idaho?
What will be an ideal response?
The difference between open and closed systems is that
A. open systems can acquire matter and energy, but closed systems cannot. B. open systems are not predictable but closed systems are. C. open systems are much simpler in terms of the number of interactions between objects in the system. D. open systems occur on land and closed systems occur in the ocean.