Physics 5A Arithmetic, Population and Energy Fall 2021 The assignment for DL is to watch the video, Arithmetic, Population and Energy, and answer the questions on this worksheet

Physics 5A Arithmetic, Population and Energy Fall 2021

The assignment for DL is to watch the video, Arithmetic, Population and Energy, and answer the questions on this worksheet.

1. Using the rule of 70, calculate the doubling time for an investment that is increasing at a rate of 3.5%/year.

2. Fill in the next row of this table for number of grains of rice on the squares of a chessboard.

3. How many rice grains will be square number 16?

4. Since 1960, the carbon-dioxide (CO₂) concentration in the atmosphere has increased from about 320 parts per million (ppm) to 412 ppm. This is a growth rate of approximately 0.45%. Use the rule of 70 to determine when will the CO₂ concentration in the atmosphere will be twice what it was in 1960?

5. According to the video (or you can do the calculation yourself), if the world wide population growth continued at the rate of 1.3%/year, how many years would it be before the would be one person fore each square meter of Earth’s surface?

6. Coal production and use has been on a continuous slide downward for economic reasons; cost of extraction, relative cost of coal vs. other forms of energy, and coal being a much dirtier form of energy than any of the alternatives. Ignoring these facts what is so dangerous about the statement that we have enough coal at present rate of use to last for 500 years?

7. Since 1986, US natural gas extraction has gone from 19 million cubic feet per year to 40 million cubic feet per year due to hydraulic fracturing (fracking). Methane is by many considered a “cleaner” fuel because it produces more energy for each unit burned, produces fewer soot and other fine particles, and doesn’t leave ash or other solid byproduct like coal. That doesn’t take into consideration other effects such as significantly increasing the frequency and intensity of earthquakes, polluting aquifers, or the fact that each Methane molecule that is released without being burned is 30-50+ times more potent as a greenhouse gas than is CO₂.

Ignore the negative effects that increased natural gas development can have, and only consider it as a possible energy source Assume with the use of fracking we have 8 times more energy available that we did with conventional oil, energy use from fossil fuels is still consistently increasing by 7% per year, and we’ve used more than half of all oil that can be extracted by conventional means.

1. What is the doubling time for the use of fossil fuels?