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Does anybody know, which motor / machine exactly is shown here? Thanks a lot.-- Tostman ( talk) 11:07, 26 September 2017 (UTC)
[1] is a homework question. I don't understand it. If the air inside the pot counters the atmospheric pressure, then all we need for water to boil is when the water vapor cancels out the weight of the lid, which is 4*gravitational constant. Area of lid is pi/100, which gives me a needed water vapor of 1.249 kPa, which according to a water vapor pressure table is achieved when water is just 7 degrees Celsius. This doesn't make sense.
Alternatively, according to the professor, we are to solve the problem by cancelling out the atmospheric pressure and lid weight with the water vapor pressure. Then the required water vapor pressure is 102 kPa. I don't know how to find the temperature of water from this, but I assume it'll be just under 101 degrees Celsius. This number makes more sense, but I don't believe the logic. I don't see how we can ignore air inside the pot. Imagine Reason ( talk) 11:50, 26 September 2017 (UTC)
Suppose someone who's a little overweight is steadily losing weight, while maintaining a constant (and significant) level of physical activity. It seems obvious that, as weight declines, the physical activity itself becomes less strenuous, possibly making it difficult for the person to maintain the same level of strength, especially in the legs, and also reducing caloric output.
Have there been any good studies comparing different ways of compensating for this, through, say, ankle, wrist, or waist weights, worn throughout the day or at least while walking for exercise? For example, is one option more effective at maintaining leg strength or caloric output? Is one option safer than another in terms of effect on joints or tendons? -- Trovatore ( talk) 18:08, 26 September 2017 (UTC)
Why using shade balls when it's possible to just cover the reservoirs and ponds with a single large tent-like sheet from sun-screening material? Also, potentially the balls may enter some sort of weak chemical reaction with the water, unlike the large tent. Thanks. 212.180.235.46 ( talk) 20:14, 26 September 2017 (UTC)
1. 10% bleach, 70% ethanol, 70% isopropanol, and 3% hydrogen peroxide, they are all better at killing gram-positive bacteria than gram-negative bacteria. What are some things that kill gram-negative bacteria better than gram-positive? I asked a microbio professor, who says "whatever kills lipid A and LPS better." So, Wikipedia shows both of those are stuff found in gram-negative bacteria. So my new question is, what's something that can destroy lipid A and LPS?
2. Can there be a bacteria that produces endospores, and be gram-negative and aerobic?
3. Are there any benefits to having obligate anaerobes in our intestines, such as Clostridium? It's beneficial to have E. coli in our intestines because E. coli prevents anaerobes like Clostridium from taking over, so.
4. We have chemicals that kill viruses and bacteria, and bacteria only. For example, O3 is a chemical that kills bacteria but does not kill viruses. But are there any chemicals that kill viruses but not bacteria?
5. This 1 I have the answer to, but I'll take feedback. There are bacteria that kill bacteria, viruses that kill other viruses, and viruses that kill bacteria. However, there isn't any bacteria that kill viruses. Is it because we haven't found any yet, or also because we don't think it's very easy for them to. Thanks. 12.239.13.143 ( talk) 20:36, 26 September 2017 (UTC).
Science desk | ||
---|---|---|
< September 25 | << Aug | September | Oct >> | September 27 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
Does anybody know, which motor / machine exactly is shown here? Thanks a lot.-- Tostman ( talk) 11:07, 26 September 2017 (UTC)
[1] is a homework question. I don't understand it. If the air inside the pot counters the atmospheric pressure, then all we need for water to boil is when the water vapor cancels out the weight of the lid, which is 4*gravitational constant. Area of lid is pi/100, which gives me a needed water vapor of 1.249 kPa, which according to a water vapor pressure table is achieved when water is just 7 degrees Celsius. This doesn't make sense.
Alternatively, according to the professor, we are to solve the problem by cancelling out the atmospheric pressure and lid weight with the water vapor pressure. Then the required water vapor pressure is 102 kPa. I don't know how to find the temperature of water from this, but I assume it'll be just under 101 degrees Celsius. This number makes more sense, but I don't believe the logic. I don't see how we can ignore air inside the pot. Imagine Reason ( talk) 11:50, 26 September 2017 (UTC)
Suppose someone who's a little overweight is steadily losing weight, while maintaining a constant (and significant) level of physical activity. It seems obvious that, as weight declines, the physical activity itself becomes less strenuous, possibly making it difficult for the person to maintain the same level of strength, especially in the legs, and also reducing caloric output.
Have there been any good studies comparing different ways of compensating for this, through, say, ankle, wrist, or waist weights, worn throughout the day or at least while walking for exercise? For example, is one option more effective at maintaining leg strength or caloric output? Is one option safer than another in terms of effect on joints or tendons? -- Trovatore ( talk) 18:08, 26 September 2017 (UTC)
Why using shade balls when it's possible to just cover the reservoirs and ponds with a single large tent-like sheet from sun-screening material? Also, potentially the balls may enter some sort of weak chemical reaction with the water, unlike the large tent. Thanks. 212.180.235.46 ( talk) 20:14, 26 September 2017 (UTC)
1. 10% bleach, 70% ethanol, 70% isopropanol, and 3% hydrogen peroxide, they are all better at killing gram-positive bacteria than gram-negative bacteria. What are some things that kill gram-negative bacteria better than gram-positive? I asked a microbio professor, who says "whatever kills lipid A and LPS better." So, Wikipedia shows both of those are stuff found in gram-negative bacteria. So my new question is, what's something that can destroy lipid A and LPS?
2. Can there be a bacteria that produces endospores, and be gram-negative and aerobic?
3. Are there any benefits to having obligate anaerobes in our intestines, such as Clostridium? It's beneficial to have E. coli in our intestines because E. coli prevents anaerobes like Clostridium from taking over, so.
4. We have chemicals that kill viruses and bacteria, and bacteria only. For example, O3 is a chemical that kills bacteria but does not kill viruses. But are there any chemicals that kill viruses but not bacteria?
5. This 1 I have the answer to, but I'll take feedback. There are bacteria that kill bacteria, viruses that kill other viruses, and viruses that kill bacteria. However, there isn't any bacteria that kill viruses. Is it because we haven't found any yet, or also because we don't think it's very easy for them to. Thanks. 12.239.13.143 ( talk) 20:36, 26 September 2017 (UTC).