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Anonymous users2024-01-24[Problem solving ideas and methods].
This is a comprehensive problem that uses pressure, buoyancy and other knowledge to solve practical problems, involving many physical formulas and physical processes. For such problems, students should not be in a hurry to solve them, but first analyze the physical process according to the required quantities and known quantities, form solutions to the problems, and then make specific calculations.
Analysis method: the depth of water in the tank is required, according to Figure 21, the length of the thin wire is known, the thickness of the valve C, and the depth of the pontoon B in the water is known again. The depth of pontoon B in the water is determined by the force it is subjected to.
Perform a force analysis on the buoy B: subject to the upward buoyancy force, the downward gravity, the downward pull force of the valve on it. Because B is stationary, there is:
F float = GB+ F pull, according to Archimedes' principle, F float contains the volume of B in the water, that is, the depth in the water, but the size of F pull is not known.
Perform a force analysis on valve C: subject to upward tension and downward pressure. Because C is at rest, there is: F pull = F pressure.
The tensile force of C is equal to the tensile force of C to B, and F pressure = PSC , P = (h+l)g
At this point, the students can see that the depth of B in the water can be found by using F float = GB+ F pull, and then the depth of the water in the tank.
Reference answer] Let the depth of float B immersed in water be h when valve C is just opened.
F float = GB+F pull.
F-pull = F-pressure.
Because F-pull = F-pull.
So F float = GB + F pressure.
Water gSBh = mBg + water gSC (h + l).
Bring in the data to solve: h = 30cm
Then the water depth is: H=h+ l+d
30cm+10cm+=
<> full of Sun Li's scattered words, please then rotten rough -v-
After the water tank is filled with water, the cover Q is subjected to the downward pressure of the water (the air below Q is not subject to buoyancy), and the pontoon P is subjected to the buoyancy of the water upward, and only the buoyancy is greater than the pressure, P can pull the Q up and realize automatic flushing. >>>More
Generally, if you like this, you must have to complain to the urban construction, and generally the kind of people who clean or manage public toilets are all people who are in pieces, and you can complain there.
Hello. It is an automatic flush controlled by the clutch. >>>More
It may be that the downtown area has a large flow of people, so if you use an automatic flushing device. It's more cost-effective, some. In places with fewer people, using this device may consume more power.