Find nine physics questions, nine physics questions

1. Multiple choice questions (3 points per question, 24 points in total).

1 When one end of the iron rod A is near the middle of the iron rod B, and the two are attracted, and when the end of B is near the middle of the A, two.

If they are not attracted to each other, then: (

A A is magnetic, B is non-magnetic B A is non-magnetic, B is magnetic.

c A and B are both magnetic D A and B are non-magnetic.

2 The following electrical equipment works using the chemical effect of electric current: (A soldering iron B Electric bell.

c motor d electrified water splitting installation.

What version of the textbook is used, not the people's education version.

13) Normal of both lights.

Operating current: i1 p1 u1 3 6 amps from p ui.

Similarly, i2 p2 u2 6 6 1 amp.

Because the two lights are used in series. So the currents are equal. That current should be 1 amp as the normal working current. Otherwise light 2 will be.

Burnout. The resistance of lamp 1: obtained by p ui u 2 r, r1 u1 2 p1 = 6 * 6 3 = 12 ohms.

Then the voltage U1 accounted for by lamp 1 in series connection'=i2r1=1*12=12 volts.

So, when two lights are connected in series, even if one light is normal.

If the light is lightened so that the actual power of the other lamp does not exceed the rated power, the voltage applied to both ends of the human circuit should be: U U1'+u2 18+6 24 volts.

The actual total power of the two lights P total u total i2 18*1 18 watts.

(1) The contact area of the person with the wooden board is the bottom area of the two feet, p1 = f1 s1 = 500n 4*10 (-2) m2 = (2) The contact area between the person and the wooden board and the ground is the area of the wooden plank p2 = f2 s2 = (500 + 100) n

1 cm has = 10 8, 1 square centimeter has 10 16, population 6x10 9, how many times?

Divide the length of the side by the diameter of the molecule (remember to convert the unit) to get the number of molecules on each edge, and the square of the number of molecules is equal to the total number of molecules. The total number of molecules divided by 6 billion is a multiple.

Electricity can be supplied.

This amount of electricity is equivalent to 1,200,000 to 3,600,000 (the energy released by the complete combustion of coal.

q1= j×2×3=

q2=50%q1=

t=q2/cm=

1 The amount of matter contained in an object is called mass, which is a fundamental property of an object, and its magnitude does not vary with the state of the object. Shape. Change of position (this is the original sentence in the textbook, flip through the book and take a look).

2 After 5kg of water freezes, the mass of the ice is 5 kg, and the mass of taking it to the moon is 5kg ( This can be deduced from the conclusion of the previous question Water turns ice or takes it to the moon state. Shape. The location has changed, but the quality has not changed).

3 Let's give you some knowledge first: 1000mg=1g, 1000g=1kg, 1kg=1000000 mg

1t =1000kg=1000000g=10000000000mg

1) 10 to the fifth power is to shift the decimal point to the right by 5 digits = 480000kg

So 10 to the fifth power = 480000kg = 480000000g = 480000000000 mg

You can go back and scold your teacher, this kind of conversion question is not a test of mental power, it is a test of physical strength, it is not difficult, it is troublesome.

2)(3) 350kg=

4) 2kg=2000g=2000000mg

4 The mass of the Sun is about n times that of the Earth (m too is the mass of the Sun and m is the mass of the Earth.

m is the mass of the sun divided by the mass of the earth n is the ratio).

5 This question feels like you have made a mistake, can you check it again to see if you have made a mistake? Word-by-word comparison of the game code weight don't do it.

Mixed and mass units kg and g are you wrong?

In addition, the fourth question: Is there a picture? Or is there a given the size of m and m too

I will continue to follow your questions.

1. The amount of matter contained in a substance is called mass, which is the basic property of an object, and its size does not change with the change of shape, volume, position, and temperature.

5kg。3. (Read: multiplied by 10 to the 5th power, the same below) 350kg=

2kg=2000g=2*10^6mg

4. I don't quite understand what you mean, provide two answers for you to choose, m too m 330,000 5, still don't understand your question, maybe you are wrong, but tell you the idea, if the object and the weight are reversed, the mass of the object is equal to the mass of the weight minus the reading of the code.

1.The amount of matter contained in an object Basic properties of state, shape, temperature, position in space.

2. 5kg 5kg

3.(1) The question is wrong: (2) 6800 6800000 (3) 350000 (4) 2000 2000000.

Solve the problem with mechanical efficiency:

w has +w total w, the extra work is the work done to overcome friction, and the distance of friction is 1000 meters.

gh+60000*20+

f＝4800n

W has =gh=60000n 20m=

w extra = fl =

w total = w has + w extra =

w total = f pulls l

f=wTotal l=

First do the decomposition of the force, because the parameters of the inclined plane are to understand the right triangle.

Splits gravity into downward and perpendicular inclined forces.

The force of the perpendicular bevel is further multiplied.

Derive the frictional force.

Friction + gravity in the direction of the inclined plane = traction.

Let me explain.

Because of the constant speed, the force of the car is balanced.

Traction force = friction of the car + gravity on the inclined plane opposite to the motion of the component = 60000*

It's about speed, or giving power.