No clue about this problem (Saving the Earth.)

[zero000]

Global warming problem (Saving the Earth.)

This is the problem:
The Earth's oceans have risen by 20 centimeters over the last 50 years. Suppose that global warming and the rise of the Earth's oceans becomes inevitable, and our only option is to find ways to lower the sea level. One option would be to dig sand from underneath the ocean and place it on dry land. This process requires energy because the sand is being raised to a higher gravitational potential energy. Estimate how much energy would be required to lower the sea level by 1 cm. Assume that the sand is raised by a height of 10 meters, that the density of sand is 2000 kilograms per cubic meter, and that the whole process uses energy at 20 percent efficiency. How does this amount of energy compare to the total energy used by civilization in one year? How much new land would be created? Note: Approximate freely as needed.

I have no clue to where i should even start. I've been sittin, starring, trying to figure it out, but the way the prof doesn't give us any notes or anything - i doubt that i can get anywhere with this. any help is appreciatedd

 

[dynamicsolo]

The oceans cover about 70% of the surface of the Earth, so you need to find the surface area of a sphere the size of Earth and take 0.7 of that. If you multiply that area by a thickness of 1 cm. = 0.01 m, you will have an estimate of the volume of sand that would need to be moved.

You are given a density for sand, so you can find the mass of sand that has to be moved.

The energy required to move all this mass is taken to be the work required to lift its weight by a distance of 10 meters (I've no idea why this number is chosen -- the average ocean depth is 1 kilometer!). Since the process does this work at 20% efficiency, that means 5 times as much energy is consumed from the fuel source than is used to actually do this work.

I don't know what the intent of the question about the "new land created" is. It seems to me that if you're dumping this sand on dry land, you aren't adding any new surface area above the water level.

You will find that, for the amount of energy required to do this, this proposal is a pretty dumb idea...

 

[Moetasim]

As a scientist, it is important to approach problems with a systematic and analytical mindset. The first step would be to break down the problem into smaller, more manageable parts. In this case, we can start by calculating the amount of energy required to lower the sea level by 1 cm using the given information.

First, we need to calculate the volume of sand needed to lower the sea level by 1 cm. This can be done by multiplying the surface area of the Earth's oceans (approximately 360 million square kilometers) by the desired depth (1 cm or 0.01 meters). This gives us a volume of 3.6 million cubic kilometers.

Next, we can calculate the mass of this sand by multiplying the volume by the density of sand (2000 kg/m^3). This gives us a total mass of 7.2 trillion kilograms.

To raise this amount of sand by a height of 10 meters, we need to calculate the potential energy using the formula PE = mgh, where m is the mass, g is the acceleration due to gravity (9.8 m/s^2), and h is the height. This gives us a potential energy of approximately 7.06 x 10^17 Joules.

However, the process of raising the sand will not be 100% efficient. The problem states that it will use energy at 20% efficiency, so we need to divide the calculated potential energy by 0.2. This gives us a total energy requirement of approximately 3.53 x 10^18 Joules.

To put this amount of energy into perspective, the total energy used by civilization in one year is estimated to be around 5 x 10^20 Joules. This means that the energy required to lower the sea level by 1 cm would be less than 1% of the total energy used by civilization in one year.

In terms of new land created, it is difficult to estimate as it would depend on factors such as the topography and composition of the dry land where the sand is placed. However, it is important to note that this solution may not be sustainable in the long term, as it requires a significant amount of energy and could potentially have negative impacts on the environment.

In conclusion, while this solution may seem feasible on a small scale, it is not a practical long-term solution for lowering sea levels. As scientists, it is important for us to continue researching and finding sustainable solutions to address