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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?
Because the density of solid B is 0.5g/cm3, and the density of liquid a is 1g / cm3, a solid solid composed of substance B is put into a container with enough substance A. when the substance B is still, the floating buoyancy = gravity = PGV = 500kg / m3 * 9.8N / kg * 0.001m3 = 4.9n, the volume of liquid f floating = PGV = 1000kg / m3
On buoyancy
Now there is a hollow toothpaste skin, a large glass of water and a measuring cylinder. Please design an experiment to calculate the density of toothpaste skin
There's no balance, no spring dynamometer or anything~
Because this is the connection of buoyancy chapter, it is estimated that it is related to buoyancy~
First thx~
Try this:
Fill the measuring cylinder with proper amount of water and record the scale v0
Immerse (sink) all the toothpaste skin in the water of the measuring cylinder (the hollow part also has water), and record the scale v1
Toothpaste skin volume = v1-v0
Take out the toothpaste skin, do not take out the water in the hollow part, let it float in the water of the measuring cylinder (there is no water in the hollow part), and record the scale
Volume of water discharged from toothpaste skin = v2-v0
G = f = water density × g × (v2-v0) toothpaste skin mass = water density × (v2-v0)
Toothpaste skin density = water density × (v2-v0) / (v1-v0)
Typing good trouble, tired s... I hope you can understand
come on.
How can I do it, someone answered? I won't answer later, typing is slow
All the scientific formulas in Volume I of the second grade of junior high school should be handed in, and the deformation formula should also include,,,, buoyancy
Don't be too stingy, want the final exam ~ ~ ~ the topic is wrong, all of them have to be!!!
Density ρ = m / V pressure P = f / s buoyancy ① f floating = g – f ② floating and suspending: F floating = g ③ f floating = g row = ρ liquid g V row series circuit current I (a) I = I1 = I2 = The current is equal everywhere and the voltage U (V) u = U1 + U2 + The series circuit acts as a voltage divider, and the resistance R (Ω
Someone uses a movable pulley to lift a bucket of water 0.5m high at a constant speed with a force of 100N. At the same time, the length of the rope is 1m. How much work has he done in this process?
What is the velocity of uniform velocity? If kinetic energy and energy loss are not considered, all the work done by that person is converted into the gravitational potential energy of the barrel, EP = mg △ H = f · s = 100 * 1 = 100J
Junior high school physics all electrical and pulley formula. To all! To have applicable conditions! And explain each formula
Speed formula physical quantity calculation formula international main unit common unit conversion relation speed v v v = s / T m / s km / h 1m / S = 3.6km/h distance s s s = VT m km 1km = 1000m time t t t = s / v s h 1H = 60min = 3600s distance s when a train crosses a bridge (tunnel)
The problem of solving various mechanical efficiency of pulley in Physics
Like the title,
Vertical pulley block (picture: one fixed pulley, two movable pulleys, starting point on fixed pulley, n = 4)
Xiaoming uses pulley block to pull up a 600N object. The object rises by 2m. The force Xiaoming uses is 200N and the mechanical efficiency of pulley block (pulley weight and rope friction are ignored)
Known: g = 600N, H = 2m, f = 200N, n = 4
For: η
Gh Gh 600N*2m
η=——*100%=——*100%=-----------*100%=75%
Fs Fns 200N*4*2m
A: the mechanical efficiency of this pulley block is 75%
As shown in the figure, the weight and friction of the rope are not included: (1) please use the three pulleys shown in the figure to make up the complete winding of the pulley block; (2) when the weight of the object is 50N, the rope end needs 20n tension to make the object rise at a uniform speed. What is the mechanical efficiency of the pulley block at this time? (3) When the weight of the rope is 90N, how much tension is needed to make it rise at a constant speed? (4) If the maximum tension that the rope can bear is 60N, how many objects can the pulley block lift?
(1) Fix one end of the rope on the hook of the fixed pulley, and then wind it in turn, as shown in the figure below: (2) at this time, the mechanical efficiency of the pulley block: η = w, W, total × 100% = ghfs × 100% = g4f × 100% = 50n4 × 20n × 100% = 62.5%; (3) the weight and friction of the rope are not included. According to f = 14 (G + G dynamic), the gravity of the moving pulley block: G dynamic = nf-g = 4 × 20n-50n = 30n, when the weight is 90N, the rope end needs to be adjusted (4) if the maximum tension the rope can bear is 60N, the maximum lifting weight is: G ″ = 4f ″ - gdynamic = 4 × 60n-30n = 200N. (2) when the weight is 50N, the rope end needs 20n tension to make the object rise at a uniform speed, and the mechanical efficiency of the pulley block is 62.5%; (3) when the weight is 90N, the rope end needs 30n tension (4) if the maximum tension the rope can bear is 60N, the pulley block can lift 200N objects
A problem of physical pulley and mechanical efficiency,
As shown in the figure, under the action of tensile force F, object a moves in a straight line at a speed of 5cmgs on the horizontal ground at a constant speed. At this time, the indication of spring force and is 3N. The mechanical efficiency of pulley is 75%. Find out (1) the size of friction force F and tensile force F on object a
The picture shows a moving pulley rope with one free end pulling object a horizontally, the other end pulling spring to measure the force, and the other end of the spring dynamometer is fixed on the wall
The answer given in the book is f = 4.8n. How can we calculate it?
I don't have permission to insert pictures. Is there any other way
The decomposition of stress condition is related to stress angle, stress condition and so on
What are the formulas of pulley block?
Mechanical efficiency of pulley block: (ignoring rope weight and friction)
When used to lift heavy objects: η = wyou / wtotal
=G / n.f
=G object / g object + G motion (g motion is the weight of moving pulley)
=Gh/Fs
When it is used to move objects horizontally (i.e. to overcome friction)
η = F.S object / F.S rope
=F / N. f (F is the friction force on the object, s is the object, s is the distance that the object and the rope move respectively)
Let f (n) = 2n + 1 (n belongs to n *), G (n) = 3 when n = 1, G (n) = f (g (n-1)) when n > = 2, find the general formula of G (n)
n> G (n) = 2g (n) = f (g (n-1)) g (n) = 2g (n-1) + 1g (n) + 1 = 2 [g (n-1) + 1] (n > = 2) because g (1) = 3, G (1) + 1 = 4, so {g (n) + 1} is an equal ratio sequence with G (1) + 1 = 4 as the first term and 2 as the common ratio. So g (n) + 1 = 4 * 2 ^ (n-1) = 2 ^ (n + 1) (n > = 1, belonging to n *). Therefore, the general formula of G (n) is: G (n) = 2 ^ (n + 1
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- 1. All formulas of buoyancy Buoyancy knowledge explains all the variant formulas of buoyancy
- 2. The meaning and calculation formula of 1 ＼ G 2. On buoyancy formula
- 3. The formula of buoyancy
- 4. 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)______ ．
- 5. Typical problems in junior high school physics
- 6. 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
- 7. 1. The buoyancy of a small ball with a volume of 2x10 cubic meters and a volume of negative cubic meters is - Niu if it is completely immersed in water. If half of its volume is immersed in water, the buoyancy is - Niu 2. When the gravity of the metal block is 26.5n and the metal block is suspended by a spring scale and immersed in water, the indication of the spring scale is 16.7n. The buoyancy of the metal block under water is - n 3. An object weighing 4 N, with a volume of 0.5 cubic decimeter, will be completely immersed in water, and the buoyancy it receives is - cow, it will lose weight in water—— 4. If a piece of wood weighs 20n and floats on the surface of the water and is still, the buoyancy of the piece of wood to the water is - Niu 5. An ocean going ship sailed into the Huangpu River from the East China Sea. The ship realized the buoyancy it received
- 8. How is the buoyancy formula derived?
- 9. How to deduce the formula of buoyancy?
- 10. Calculation formula of water buoyancy V row It is the calculation formula of V row, f floating = P liquid GV row
- 11. 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
- 12. 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
- 13. 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.
- 14. All the formulas for buoyancy and pressure
- 15. 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
- 16. 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
- 17. Under what conditions is f floating = ρ liquid GV discharged, under what conditions is f floating = g discharged, f floating = m discharged, G discharged
- 18. The physical meaning of G = 9.8n/kg is______ ．
- 19. What's the meaning of ml / dl? How to read it? What's the difference between ml / dl and Mg / dl
- 20. Conversion of kg and Mg 72kg = 10 to the seventh power mg