What are the steps to prevent soil erosion in hilly areas?
What reduces erosion is essentially whatever holds the soil and rock particles in place. This can be natural or human made.Natural bares to erosion include:soil cover (that reduces erosion of the bedrock)plant cover:any root systems, be it from grass or trees or anything in between, will hold soil in place, somewhat.Man made bares include:terraces (they essentially remove gravity as a factor and serve as a barrier for eroded material- you can see this in action in most wine rich areas),A somewhat unusual set of terraces, planted with young grapevines.Rice paddies on terraces - South East Asia.retaining walls (they hold hillsides in place, etc.),anchors (they mimic the action of roots, holding hillsides in place),Here you can see a retaining wall in the back and where anchors are used in the front-bottom (the grey cylindrical pieces are covering them).afforestation (planting trees to achieve the desired effect).A community afforestation action - can be a contracted job, done by professionals.There are some other techniques for reducing erosion, all are applicable in almost any landscape, but most importantly, none can prevent erosion entirely, lest we level every mountain and hill on Earth under water and then drain the oceans somehow. Even then, there would still be some erosion going on somewhere. We can’t create a perfectly smooth sphere in a factory, let alone make one out of Earth and as long as there is some slope, there will be some erosion going on. As well as accumulation.
Physics mass defect question, help please!!?
A 223-kg boulder is dropped into a mine shaft that is 3.20 103 deep. During the boulder's fall, the system consisting of the earth and the boulder loses a certain amount of gravitational potential energy. It would take an equal amount of energy to "free" the boulder from the shaft by raising it back to the top, so this can be considered the system's binding energy. (a) Determine the binding energy (in joules) of the earth-boulder system. (b) How much mass does the earth-boulder system lose when the boulder falls to the bottom of the shaft? I know once I figure out the binding energy I can use the equation binding energy/c^2 = delta m but I have no idea how to find the binding energy in this situation
How much devastation would a 150lb rock (going as close as possible to the speed of light without going at the speed of light ) do to Earth?
Tiny changes in speed make a huge difference here when we’re talking about speeds near the speed of light. As a result, “close as possible” to the speed of light makes this question quite tricky.But to give you a few ideas, let’s look at some numbers.First, I’m going to call this a 68kg rock. Metric system!Let’s look at various speeds and compare:Less than 1% of the speed of light. For these speeds, the relativistic effects are small, and the explosions are, too (relatively speaking…we’ll be getting into some huge numbers momentarily). At 1% of c, the energy released is equivalent to around 4.87 Hiroshima bombs. Devastation is nearly 100% over an area of several miles, but overall the Earth is unaffected.From 1% to 99% of the speed of light. For these speeds, the relativistic effects start small but build to be pretty significant. At 99% of c, the energy released is equivalent to nearly 9 GT of TNT, or around 600,000 Hiroshima bombs. It is still, however, just a tiny fraction of the amount of energy released by the Chicxulub impact that wiped out the dinosaurs. Whatever you hit at these speeds is instantly obliterated, and regional extinctions are likely the nearer you get to 99% of c, but life survives.Adding 9’s after the decimal point. For these speeds, the relativistic effects get enormous, making our 68kg rock behave more like a huge asteroid. At around 0.99999999994c, we have the equivalent of Chicxulub. The planet is devastated, and the Earth is thrown into a hellish climate nightmare of endless darkness, planet-wide fires, and mass extinctions. Life still survives, however. At 0.999999999999996c, we have the equivalent of a billion Hiroshima bombs, or around 126 Chicxulubs (best unit ever, btw). This probably wipes out life on Earth, or at the very least multicellular life.Obliterating the Earth. The binding energy of the Earth is around 2E32J. To get our explosion to that energy, we’ll need to accelerate our 68kg rock to 0.99999999999999999999999999953c. Just calculating this number pressed the limits of my calculating power - we’re so close to the speed of light that we’ve effectively increased the mass of our rock by a factor of nearly 33 trillion. That gives it an effective mass nearly the same as Deimos, a moon with a radius of over 6 kilometers.So as you can see, when you say close to the speed of light, the degree of closeness makes a big difference!
What are the advantages and disadvantages of representative democracy compared to direct democracy?
It would be hard to make a comparison.Representative democracy requires high levels of trust in the ability of representatives to make decisions that represent the wishes and interests of the constituency. Direct Democracy requires high levels of political engagement, and a relatively high degree of understanding of the subject matter being decided on. Which means relatively high levels of education, and low levels of economic inequality, are quite important (though not deal-breakers).We would have to establish what constitutes "better" in order to make a comparison.If by "better" we mean lower levels of corruption, higher levels of service delivery by government, and a higher degree of regulatory innovation, then Direct Democracy is almost certainly a better system.If by "better" we mean government more responsive to industry interests, an electoral process that is easier to install and maintain, and a legislative process that promotes conservative values by rejecting the majority of legal changes, then a Democratic Republic is the better system.Personally, I feel like a Representative Democracy incentivizes disengaging from the political sphere, making Direct Democracy virtually impossible to implement. And, Ironically, I think that Direct Democracy is more representative of the interests of the public than a Representative Democracy could ever be.Finally, we've entered the digital age, and as such should be seeing the democratic process reflect the technical and technological advance we're making as a species. Unfortunately, Representative Democracy is deeply entrenched in global geo-politics, and is going to take a monumental effort and level of engagement by the public to be ousted by Direct Democracy. This doesn't mean it can't or shouldn't be done... merely that it won't be a simple matter of saying "let's try this new idea"For those interested in the technological means to run a direct democracy, there are several projects aimed at finding an optimal decision making platform. Here's one popular system under development: liqd/adhocracy