The process of solving the three physics problems is urgent

Question 1: 1The graduated cylinder is filled with water appropriately, the reading is v1, and the vial is submerged in water, and the reading v2 is obtained to obtain the volume of the vial (v2-v1);

2.The graduated cylinder is filled with water appropriately, the reading v3 is put into the vial to float in the water, the reading v4 is read, and the quality of the vial is [ water (v4-v3)];

3.Needless to say! (What's wrong with the vial, vent).

If the bottle is bigger than the graduated cylinder, it's the other way around.

Question 2:1Fill the measuring cup with an appropriate amount of water, read v1, put it into a small plastic box (filled with glass) to float in the water, read v2, and the quality of the glass is [ water (v2-v1)];

2.Fill the measuring cup with an appropriate amount of water, read V3, put it into the glass to submerge it in water, read V4, and the volume of the vial is water (V4-V3);

3.Needless to say!

Question 3: Pressure + Gravity = Buoyancy = Water Density Wood Volume = Water Density (Wood Gravity g Wood Density).

Ask for pressure and solve the equation yourself!

Don't be lazy!

The first question, first add an appropriate amount of water to the graduated cylinder, set V1 liter, and then add a small glass bottle, a total of V2 liters, V2 minus V1 is the volume of the small glass bottle V3, that is, equal to the volume of water V3, according to the density of water P, V3 times P is the mass of water m, which is also the mass of the glass bottle, and finally M divided by V3 is the density of the small glass bottle.

The second question works the same as the first question.

The third question, in fact, is similar to the drainage method, which is completely affected by gravity, buoyancy, and vertical downward force in the water, and the volume of water discharged is, buoyancy is, gravity, and how much vertical downward force needs to be exerted.

1. The principle of the first question is the same as that of the second question. Then I'll talk about the first question. First pour the water into the graduated cylinder, write down the volume v of the water, then let the empty glass bottle float on the surface of the water, and write down the volume of the water v1 at this time when it is stationary, so the gravity of the bottle at this time is equal to the buoyancy f = water g (v1-v) = m bottle g

Then fill the bottle with water and let it sink to the bottom, and make a note of this moment v2 when it is still. So the bottle density is =m bottle (v2-v)If you know the density of water and the acceleration of gravity, you can find it.

In the second question, fill a small cardboard box with broken glass for testing.

3. To completely immerse it in water, the buoyancy should be equal to the pressure. The magnitude of buoyancy is equal to the gravitational force of the water expelled. This problem is to ask for the volume of the wooden block (that is, the volume of water to drain).

Knowing the gravity and density of the block can be used to find the volume of the entire block. You asked for it yourself.

1) The support force n of the vertex points to the center of the sphere, and its vertical component balances the gravity, and n is obtained from the simple triangular relation: sqrt(19)*n 10=mg

The support force n' of the vertical wall is used to balance the horizontal component of n: n' = 9n 10

2) Because it is a uniform deceleration, the total time is t=2*t2=40s. The displacement in the second half is 100m (characteristic of uniform speed motion, the displacement is proportional to the square of time), so the total displacement is s=400m=v0*t2, and v0=20m s is obtained

1:30 cubic centimeters = 30 1,000,000 cubic meters, set to a then: (30 a) times kilograms is the answer.

2: The volume of water is: 1 kilogram 1000 kilograms cubic meter = cubic meter, then: the mass of oil is: multiply by 1000 = kilogram.

3: The volume of the bronze sculpture is: 445 divided by (multiplied by 1000).

Then: the mass of the wax is: multiply 1000 times 445 divided by (multiply 1000) = 45 kg.

1.is the same density, 2is the same volume, 3It is also equivalent in volume! You can do it yourself!

1) (10kW power in one hour) 40W in 250 hours, 800W*

2) 3000r, that is, one kilowatt-hour of electricity to 3000 turns, one kilowatt-hour of electricity is J3) The maximum power of the electric energy meter is 220V*5A=1100W60W+70W+150W+300W+500W=980W, yes.

1 This question examines the relationship between pressure and volume, that is, it can be solved by using the formula p1v1=p2v2 and mg s=p.

Question 2 What is the pressure of the original container? When this is opened, the pressure becomes the same as the atmospheric pressure, and the ratio is the front-to-back pressure ratio.

3. Question 3: This is first of all, considering that the liquid changes very little, and ignoring it.

So this is equivalent to filling 5 liters of 1atm air into 2 liters of volume, which is equivalent to compressing 5 liters of gas to 2 liters, using the formula for the first problem.

a, enlarged. The larger the angle between the two ropes, the smaller the resultant force, because the weight of the painting remains the same, and when the angle becomes larger, the resultant force remains the weight of the painting, which can only increase the tension of the two ropes.

1.It's hard to see things at night.

It is not easy to find a reference2 The wall of their house is a fence wall, in fact, the wind blows the fence away from its original position, using the well as a reference, and the fence crosses the mouth of the well, but in relation to the fence, that is, using the fence as a reference, the well "moves" outside the fence.

3.Downstream speed = boat speed + water speed.

Countercurrent speed = boat speed - speed of water.

This is a dead end, fold the ring with an inner diameter of 2 cm in half and fold it in half, and the four points of the inner circle are the vertices of the four corners of E. 2. Place the pencil horizontally, and draw a line with the two points of the upper line touching the inner circle, which is the upper horizontal line of e, if it is thickened, draw another line according to the lower line of the pencil. 3. Then put the pencil vertically over or the left side through the two points of the inner circle, and then draw the right line of the pencil, which is the vertical of e.

4. Use a pencil to measure the center point in the vertical position, and then you can draw the middle horizontal. 5.The speed of sound propagation in the air is known to be 340m s, and the speed of a car is 12m s.

Let the distance between the car and the cliff be s. That is, s=(340*2+12*2) 2=352m

6.The circumference of the ring = 50 cm, then the circumference of the flower bed = cm = meters.

Same issue.

*75, the work done by gravity is negative, the work done by overcoming gravity is positive, and the increase in gravitational potential energy is positive.

1. Multiply the gravity of the volleyball by the height of the fall. 2. The inclination angle is 30 degrees, the hypotenuse is 150, so the height is 75, and the gravity of the person is multiplied by 75 (all three questions are). 3. Convert the unit of the most bearing force into cattle Bungalow centimeters (easy to calculate) multiplied by the cross-sectional area is the force that can fall to the ground, divided by gravity is the height, and finally subtracted by one centimeter....It's a one-time answer, if you have any questions, it's okay to say.

3.Parse. Let the angular velocity of the two stars be w, the gravitational force between the two stars is equal to their respective centripetal force, and g is the gravitational constant:

gm1m2/l^2=m1w^2r1=m2w^2r2 =>m1r1=m2r2

again r1+r2=l

r1=m2l (m1+m2) r2=m1l (m1+m2) to get w=g(m1+m2) l 3

t=2π/w=2π*l^3/g(m1+m2

Asking so many questions at once, few people ...... high bounty scores