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All the formulas for buoyancy and pressure
1. Definition: the mass of a substance per unit volume. 2. Formula: density = mass / volume, ρ = m / V 3, unit: g / cm 3 or kg / M 3. Conversion relation: 1 g / cm 3 = 1000 thousand
At the May day entertainment party, CHEN Si demonstrated the experiment as shown in the figure. There are three bowls in a line, and a table tennis ball is placed in the middle bowl. When a small pipe is used to blow air diagonally above the ball, the table tennis ball will ()
A. Still standing B. moving to left bowl C. moving to right bowl D. not sure
When a small pipe is used to blow air obliquely above the table tennis ball, the velocity of the air above is large and the pressure is small, and the table tennis ball will rise because of an upward pressure difference. When the table tennis ball rises, the velocity of the air on the right side is large and the pressure is small, and the velocity of the air on the left side is small and the pressure is high, so the table tennis ball will move to the right side (only when the air is blown obliquely upward) And D are all incorrect
A and B are two rectangular solid blocks, which are placed on the sand and sunk into the sand at the same depth. It is known that s a > s B, h a < H B, then the density, mass and pressure relations of a and B are & nbsp; ρ a respectively______ ρ B, m a______ M B, P A______ P B
(1) ∵ A and B two cuboid solid blocks, placed on the sand, sink into the sand at the same depth, ∵ p a = P B, ∵ s a > s B, ∵ according to P = FS, f a > F B, ∵ the pressure of the object on the horizontal plane is equal to its own gravity, ∵ g a > G B, ∵ g = mg, ∵ m a > m B; (2) the pressure of the cuboid on the sand on the horizontal plane P = FS = GS = MGS = ρ VGS = ρ SHGs = ρ GH, Therefore, the answer is: >; =
Velocity is a physical quantity used to represent an object
Speed is a physical quantity used to express the speed of an object
Temperature is the temperature of an object______ Physical quantity
The degree of coldness and hotness of an object is expressed by temperature, so temperature is a physical quantity to compare the degree of coldness and hotness of an object
In physics, velocity is used to express______ The physical quantity of the system
In physics, speed is a physical quantity used to express the speed of an object
What is the speed of an object passing through? Is the speed a physical quantity used to represent the object?
Fill in according to the box you give:
The distance an object passes in unit time is called speed. Speed is a physical quantity used to express the speed and direction of an object
What is the physical quantity to describe the speed of linear motion with variable speed
Acceleration
In the process of uniform linear motion, which physical quantities appear in the expression of the law of displacement change
It is necessary to know some of the physical quantities in order to work out other physical quantities
Four
They are displacement, velocity, time and acceleration
v=v.+at
s=v.t+at²/2
v²-v.²=2as
a=(v-v.)/t
The average speed is the speed of the moving object____ Physical quantity of 22
The average value of unit time displacement in a period of time
RELATED INFORMATIONS
- 1. A course of junior high school physics [pressure and buoyancy], This is the physical simulation of Haidian District in Beijing in 2009 As shown in the figure (a cylindrical container contains a plastic box, in which an iron block floats on the water surface), the cylindrical container with bottom area S1 contains liquid with unknown density. Put a cube metal block with density ρ into the rectangular plastic box with bottom area S2 (the thickness of the plastic box can be ignored), The plastic box floats on the liquid surface (the liquid will not overflow the container), and its immersion depth is H1. If the metal block is taken out of the plastic box, it is tied under the plastic box with thin wire, and put into the liquid, the metal block does not contact the container, and the immersion depth of the plastic box is H2. Cut the thin wire, the metal block will sink to the bottom of the container, and the plastic box floats on the liquid surface, The depth of immersion is H3. If the plastic box is always upright without inclination, the pressure of the liquid on the bottom of the cylindrical container is reduced before and after the thin line is cut? Two supplementary points: 1. The density of the liquid in the container is unknown, and the expression should not contain ρ liquid. 2. The question is how much pressure has been reduced. Not why.
- 2. Who listed the related formulas of physical pressure and buoyancy one by one, including Rou = m / V, which is not published in textbooks? Don't take too many words to explain in front of me. Just tell me what the physical quantity is. I want to copy and paste it
- 3. In a bathing beach, the bottom of the water is full of stones. In the process of swimming from deep water to shallow water, the following experience and analysis are reasonable () A. Feet are getting more and more painful because water has less and less support for people. B. feet are getting more and more painful because people are receiving more and more gravity. C. feet don't hurt because people are getting lighter and lighter. D. feet don't hurt because water has more and more support for people
- 4. buoyancy A and B are liquid and solid respectively. The density of liquid a is 1g / cm3, and that of solid B is 0.5g/cm3. When a solid solid (composed of substance B) with a volume of 10-3m3 is put into a container containing enough liquid of substance A, how much buoyancy does the solid solid receive when it is still? How much volume does the liquid displace?
- 5. All formulas of buoyancy Buoyancy knowledge explains all the variant formulas of buoyancy
- 6. The meaning and calculation formula of 1 ＼ G 2. On buoyancy formula
- 7. The formula of buoyancy
- 8. Xiaohua did the experiment of "estimating the value of atmospheric pressure." (1) please complete the following experimental steps. A. push the piston of the syringe to the top of the syringe barrel______ Then seal the small hole of the syringe with a rubber cap. B. fasten the neck of the piston of the syringe with a fine nylon rope so that one end of the rope is connected with the hook of the spring dynamometer, and then pull the syringe barrel horizontally and slowly to the right______ Write it down______ It is equal to the pressure of the atmosphere on the piston, F.C______ , denoted as l, read out the volume V of the syringe, then the area s of the piston=______ Finally, the value p of atmospheric pressure at this time is calculated=______ (write the expression with the measured quantity). (2) in the experiment, Xiaohua used the measuring instrument correctly, and the reading was correct, but she found that there was always deviation in the measurement results, which may be caused by (write two points)______ ．
- 9. Typical problems in junior high school physics
- 10. As shown in the figure, a piece of lead is hung under an inflated balloon with a thin thread, put it into the water, and it is just in a static state somewhere. If some water is slowly released from the bottom, the lead and the balloon () A. Still able to stand still B. move down C. move up D. stand still. It's possible to move up or down
- 11. When measuring the density of a small solid object, a physics interest group adopted the following experimental operations: first, the mass mo of the object was measured with a balance; then, a certain amount of water was put into a small beaker, and the total mass M1 of the beaker and water was measured with a balance; then, after the object was tied up with a thin line, the mass M1 of the beaker and water was measured, The object is immersed in the water of the beaker (the water does not overflow and the object does not touch the beaker) by holding a thin line in hand. At this time, the measured value of the balance is m2, as shown in Figure 6 A. The buoyancy of an object in water is MOG B. The buoyancy of an object in water is (m2-ml) g C. The density of the object is Mo / m2-m1 * P water D. The density of the object is Mo / m2-m0 * P water 、 I don't understand at all. I'm going to take the senior high school entrance examination right away. It's really disturbing that I don't understand
- 12. Some questions about buoyancy in junior high school physics 1. A 100 cubic centimeter object is hung under the spring dynamometer. When the object is immersed in water, the indication of the spring dynamometer is 1.7n__ N 2. Put a solid aluminum block with a mass of 27g into a beaker filled with water. When the aluminum block is still in water, the mass of water discharged from the beaker is__ g. Put the aluminum block into a beaker filled with alcohol, and the mass of the discharged alcohol is__ g
- 13. Under what conditions is f floating = ρ liquid GV discharged, under what conditions is f floating = g discharged, f floating = m discharged, G discharged
- 14. The physical meaning of G = 9.8n/kg is______ ．
- 15. What's the meaning of ml / dl? How to read it? What's the difference between ml / dl and Mg / dl
- 16. Conversion of kg and Mg 72kg = 10 to the seventh power mg
- 17. What is Archimedes' formula of buoyancy principle An object is subjected to upward buoyancy, which is equal to the gravity of the liquid displaced by the object!
- 18. Why is the buoyancy equal to gravity when an object floats or floats? The volume of water overflowing during floating is different from that during suspension. Why is the buoyancy the same?
- 19. Why not use Archimedes principle to calculate the buoyancy of floating objects? The teacher said that when floating, f floating = g object can discharge liquid according to Archimedes principle. That is to say, the buoyancy has something to do with the volume of the immersed liquid. Isn't there part of the floating that is not completely submerged? How can we say that f floating = gravity? These two problems can be calculated in both aspects What kind of application is it? When and how to use it? What's the difference
- 20. The pressure on the lower surface of the board is equal to the buoyancy f = f floating = 6N?