V 2 = V 3 > V 1

2.

R

4. p h

5. To , then

6. Three bodies have the same volume. The densities of the substances from which bodies are made are related asρ 1 < ρ 2 < ρ 3 . What is the ratio between the masses of these bodies?

7. F 1 and on a cube of steelF 2 .

1. Ball 1 is sequentially weighed on a balance scale with ball 2 and ball 3 (Fig. a and b). For the volumes of spheres, the relationV 2 = V 3 > V 1 . Ball(s) have a minimum average density

2. Two identical steel balls are balanced on a balance scale (see figure). Will the balance of the balance be disturbed if one ball is lowered into engine oil and the other into gasoline?

3. A U-shaped glass vessel, the right leg of which is sealed, is filled with a liquid of densityR (see picture). The pressure exerted by a liquid on the horizontal bottom of a vessel is

4. Which of the following graphs corresponds to a change in fluid pressurep as the height of the liquid column increasesh ? Atmospheric pressure is not taken into account.

5. The open container 1 and the closed container 2 contain water. If you open the faucetTo , then

1) water will necessarily flow from vessel 2 to vessel 1

2) water will necessarily flow from vessel 1 to vessel 2

3) water will not flow under any circumstances

4) the movement of liquids will depend on the pressure in the air gap of vessel 2

7. Two cubes of the same volume, made of aluminum and steel, are lowered into a vessel with water. Compare the values ​​of the buoyancy force acting on an aluminum cubeF 1 and on a cube of steelF 2 .

10. In a vessel with water densityρ BUT , equals

ρgh 1 ρgh 1 ρg(h 1+ h 2) ρg(h 2- h 1)

11. a = 30 cm,b = 20 cm andc

12.

14.

3

8. The figure shows four beakers with different liquids of equal mass. Which beaker contains the liquid with the highest density?

9. One of the legs of the U-shaped pressure gauge was connected to a vessel filled with gas (see figure). What is the pressure of the gas in the vessel if the atmospheric pressure is 760 mm Hg. Art. (d mercury is used as the liquid in the pressure gauge)? 1) 200 mmHg Art. 2) 560 mmHg Art. 3) 760 mmHg St 4) 960 mm Hg. Art.

10. In a vessel with water densityρ a vertical glass test tube completely filled with water is lowered (see figure). The pressure exerted by water on the bottom of the vessel at a pointBUT , equals

ρgh 1 ρgh 1 ρg(h 1+ h 2) ρg(h 2- h 1)

11. Pine block in the form of a rectangular parallelepiped having dimensionsa = 30 cm,b = 20 cm andc = 10 cm, begin to carefully lower into a bath of water (as shown in the figure). How deep will the bar be immersed in water while swimming?

12. What is the volume of a fish swimming in sea water if a buoyant force of 10.3 N acts on it?

13. The tube, sealed at one end, is lowered with the open end into the water for half the length of the tube (see figure). What happens to the level of water entering the tube after the atmospheric pressure decreases? Explain the answer.

14. 1 kg of glycerin and 2 kg of water are poured into a vessel and gently mixed. Assuming that the volume of the mixture of liquids is equal to the sum of their initial volumes, determine the density of the resulting solution.

15. Solid cube with a density of 900 kg/m 3 floats on the interface between water and kerosene, plunging into the water by 4 cm (see figure). The kerosene layer is located higher than the top surface of the cube. Determine the length of the edge of the cube.

Quest Source: Decision 2440.-6. OGE 2017 Physics, E.E. Kamzeev. 30 options.

Task 5. Ball 1 is sequentially weighed on a balance with ball 2 and ball 3 (Fig. a and b). For volumes of balls, the relation V1 = V3< V2.

Ball(s) have a minimum average density

eleven; 2) 2; 3) 3; 4) 1 and 2

Decision.

The density of a substance is the ratio of the mass of a substance to its volume: r=m/V. Figure b shows that ball 1 has less mass than ball 3. And since they have the same volume V, the density of the 1st ball will be less than the density of the 3rd ball. Figure a shows that balls 1 and 2 weigh the same. However, ball 2 has a larger volume than ball 1, so ball 2 has a lower density than ball 1.

Answer: 2.

Task 6. On a body at rest, located on a smooth horizontal plane, two parallel horizontal forces begin to act (see figure). Determine how the modulus of the body's velocity and the modulus of the body's acceleration change with time.

Establish a correspondence between physical quantities and their possible changes. For each value, determine the appropriate nature of the change:

1) increases

2) decreases

3) does not change

Decision.

The resultant force acting on the body will be determined according to the law of superposition of forces, that is, the resultant in this case will be equal to

and sent to positive side x-axes. According to Newton's second law, and since the mass of the body does not change, and F>0, the body will begin to move with a constant acceleration and, accordingly, with an ever-increasing speed (since with a constant positive acceleration, the speed increases).

put in water?
1) the balance of the scales will not be disturbed, because balls of the same mass

2) outweigh the aluminum ball

3) outweigh the ball of copper

4) will not be violated, because balls are lowered into the same liquid

lever scales. Conclusion: with the help of a lever scale, you can measure ... Thanks in advance!)))))))))))

sequentially. How much will the same load stretch this structure?

2 . A glass of water is balanced on a balance scale. Vasya, a seventh-grader, dipped his little finger into this glass, without touching either the bottom or the walls, knowing that the volume of this finger was 2 cm3. Will the balance of the scales be disturbed? If so, what weight should be added to or removed from the second cup to restore balance? The density of water is 2 g/cm3.

3. A steamboat travels along the river between two points. Full time the way (there and back) is 10 hours. The speed of the steamer relative to the shore when moving with the flow is 1.5 times greater than against the flow. How long would it take for a steamboat to travel the same round trip across a lake with no current?

4. For the first third of its route, the bus moved at a speed of 20 km/h, the second third at a speed of 30 km/h, and the rest of the entire journey at 60 km/h. What is the average speed of the bus for the entire route?

5. Katya and Masha have hot coffee in cups. Katya immediately added cold milk to it and waited 5 minutes for the drink to cool. Masha first waited 5 minutes, and then added the same amount of milk to the coffee at the same temperature. Did the girls' drinks turn out to be the same temperature? The mass and initial temperature of the coffee are the same for the girls, the cups are also the same and are next to each other on the same table.

6. The flask contains water at 0°C. Pumping out the steam, they froze the water. What part of the water has evaporated? The specific heat of vaporization of water at 0 °C is assumed to be 2.5 106 J/kg, and the specific heat of fusion is assumed to be 3.4 105 J/kg.

7. Above a square carpet with a side of 4 meters, exactly above its center, at a height of 2 meters, hangs a small round bulb, radiating light evenly in all directions. What fraction of the radiation energy hits the carpet?

8. The copper wire has a circular section with an area of ​​S1=1 mm2. It is covered with a layer of silver with a thickness of d=10 µm. By what percent will the resistance of this wire change? Resistivity of copper ρ1=0.0175 Ohm mm2/m, resistivity of silver ρ2=0.016 Ohm mm2/m.

PLEASE SOLVE BEFORE TOMORROW I NEED THESE TASKS!

weights.

Conclusion: With the help of a balance scale, you can measure...

Thanks in advance!

1) a passenger walking along the carriage
2) locomotive
3) a passenger sitting in a carriage
4) table
2. To balance the body on a balance scale, a set of weights 50 g, 10 g, 10 mg, 10 mg was used. The determined body weight is equal to
1) 60.200 g
2) 70.100 g
3) 60.020 g
4) 80,000 g
3. When fired from a rifle, the bullet speed is 600 m / s, and the speed of the rifle during recoil is 1.5 m / s. From this it follows that
1) the mass of the rifle and the mass of the bullet are the same
2) the mass of the rifle is 40 times greater than the mass of the bullet
3) the mass of the rifle is 900 times greater than the mass of the bullet
4) the mass of the bullet is 400 times less than the mass of the rifle
4. 2 liters of milk were added to the milk can. Wherein
1) the mass of milk in the can has increased, the density of milk has increased
2) the volume of milk in the can has increased, the density of milk has decreased
3) the mass of milk in the can has decreased, the density of milk has not changed
4) the volume of milk in the can has increased, the density of milk has not changed

1. Task 5 No. 32

Ball 1 is sequentially weighed on a balance with ball 2 and ball 3 (Fig. a and b). The relation V2 = V3 > V1 holds true for the volumes of spheres.

By condition, for the volumes of balls, the relation V2 = V3 > V1 is valid. Let's establish the ratio between the masses of the balls, based on the weighing results: M3 > M1 > M2. Density is determined by the following formula:

Thus, we get that ρ2< ρ1, потому что шар 1 имеет меньший объем, но при этом большую массу, и ρ2 < ρ3, потому что шары 2 и 3 имеют одинаковый объем, но при этом шар 3 имеет большую массу.

2. Task 5 No. 140

In the process of heating, the steel ball stopped crawling through the metal ring (see figure).

1) the mass and density of the ball have not changed

2) the mass and density of the ball increased

3) the mass of the ball has not changed, but its density has decreased

4) the mass of the ball has not changed, but its density has increased

In the process of heating, the average kinetic energy of the molecules of the body increases. If we are talking about a solid body, then the amplitude of oscillations around the equilibrium positions of atoms increases, i.e., the volume of the body increases. This phenomenon is called "thermal expansion". Since the volume increases with the same amount of matter, the density of the body decreases.

3. Task 5 No. 167

In the process of heating a flask with a liquid placed in a vessel with hot water, an increase in the liquid level in the tube was observed (see figure). At the same time, in the flask

1) the mass and density of the liquid have not changed

2) the mass and density of the liquid have increased

3) the mass of the liquid has not changed, but its density has decreased

4) the mass of the liquid has not changed, but its density has increased

Since the flask does not communicate with the vessel, and the evaporation losses are negligible, the mass of the liquid did not change during heating. When heated, the liquid level in the tube increased, i.e., the volume increased. An increase in volume with a constant mass means a decrease in density.

The correct answer is number 3.

4. Task 5 No. 410

Three bodies have the same volume. The densities of the substances from which the bodies are made are related as ρ1< ρ2 < ρ3. Каково соотношение между массами этих тел?

Since bodies have the same volume, and density is the ratio of mass to volume, their masses are related as follows: m1< m2 < m3.

The correct answer is number 2.

5. Task 5 No. 572

The figure shows four beakers with different liquids of equal mass. Which beaker contains the liquid with the highest density?

The density of a liquid is equal to the ratio of the mass of the liquid to its volume. The liquid in the fourth beaker has the smallest volume. The mass of the liquid in all cases is equal, therefore, the density of the liquid in the fourth beaker is the highest.

The correct answer is number 4.

6. Task 5 No. 906

< V2.

Ball(s) have the maximum average density

It is clear from the figure that the mass of balls 1 and 2 is equal, therefore, the density of the second ball is less than the first one. The third ball is heavier than the first for the same volume, so the density of the third ball is greater than the density of the first. thus ball 3 has the maximum average density.

The correct answer is number 3.

7. Task 5 No. 1684

Ball 1 is sequentially weighed on a balance with ball 2 and ball 3 (Fig. a and b). For volumes of balls, the relation V1 = V3< V2.

Ball(s) have a minimum average density

Since the mass of ball 1 is equal to the mass of ball 2, and the volume of ball 1 is less than ball 2, then the average density of ball 2 is less than the density of ball 1.

The correct answer is number 2

25) there is a solution

26) in 1 vessel. Pressure depends on temperature, the higher the temperature, the faster the molecules move, which means they collide more often. The pressure is increasing.

1 kg of glycerin and 2 kg of water are poured into a vessel and gently mixed. Assuming that the volume of the mixture of liquids is equal to the sum of their initial volumes, determine the density of the resulting solution.

The volumes of glycerin and water are equal:

Mixture weight:

The density of the resulting mixture.