Physics Help Me 10

1.Originally, the angle between the incident light and the mirror is 90 degrees, and after 20 degrees, the angle between the incident light and the mirror is 70 degrees, so the angle between the outgoing light and the mirror is also 70 degrees, so the angle between the incident and the outgoing light is 180-70-70=40

2.Boiling is 100 degrees.

1).Then the amount of heat required is q= c*m*(t2-t1)= j2) kg"At least"This means that because the heat produced by coal is not 100% converted into the heat energy of water, a large part of it is wasted, so it will only need more.

3) Mainly the incomplete combustion of coal and the dissipation of heat to the surroundings.

4) The burning of coal produces a lot of carbon dioxide and carbon monoxide that pollute the air.

1.Turning the plane mirror 20 degrees is equivalent to an angle of incidence of 20 degrees, because the angle of incidence is equal to the angle of reflection, then the angle between the incident ray and the reflected ray is 40 degrees.

2。This involves the problem of specific heat, which has a boiling point of 100 degrees Celsius at standard atmospheric pressure. The specific heat of water is .

Xiao Mingjia needs J to boil water and cook rice every day

At least it means the least amount of energy required to boil water, cook rice, and stir-fry without any loss of energy.

3。The main thing is the incomplete combustion of coal and the dissipation of heat to the surroundings.

4。The incomplete combustion of coal will produce carbon dioxide, which will lead to a rise in global temperatures, carbon monoxide death, and sulfur dioxide will cause the formation of acid rain and pollute the environment.

Degree. 2.Boiling is 100 degrees.

1).Then the amount of heat required is q= c*m*(t2-t1)= j2) kg"At least"This means that because the heat produced by coal is not 100% converted into the heat energy of water, a large part of it is wasted, so it will only need more.

3) Mainly the incomplete combustion of coal and the dissipation of heat to the surrounding area 4) The combustion of coal produces large amounts of carbon dioxide and carbon monoxide, which pollute the air.

I'll try: 1:40 degrees.

2: It's boring to do this kind of thing after learning the knowledge of heat, I haven't learned it yet, and I don't know.

1 40 degrees 2 10080000 coul If the heat is not lost, how many kilograms of coal can be burned to reach 10080000 coul3 When coal is burned, heat will be dissipated and not fully burned 4. Combustion will produce carbon dioxide, which will aggravate the greenhouse effect; Sulphur dioxide causes acid rain and damages the environment.

According to the title, the rope is pulled downward. The moment of tensile force f is balanced with the moment of g, mf = mg

FSIN 30°*, the ball to the plate pressure is 5N. When the ball has moved l meters, the pulling force of the rope is zero. At this time, the moment of pressure of the ball on the plate and the moment of g are balanced. Namely.

5L=mg=,L=m, T=Lv=s.

The usual hospital ** fallopian tube blockage is the method of water clearance, but the effect is not very good, now there are some very good technologies, and there are many hospitals under the banner of advanced technology to deceive patients, these should be noted. **Be sure to go to a regular hospital. Xie, located in Chongqing.

And the hospital's 3G-GBT pregnancy mirror diagnosis and treatment system is imported from the United States, my colleague has used this system, and the effect can be guaranteed. There are many hospitals now, and when choosing a hospital, you must pay attention to it, beware everywhere, and avoid being deceived!

Consider the true direction of velocity of a as the direction of a and the direction of velocity, that is, vertically upward. Break it down into velocity in the direction of the rope (equal to vb) and velocity perpendicular to the rope. You know vb=va*cos.

Isn't the topic complete? Is the object in motion? Straightening? Or is it stationary, or is it accelerating? Acceleration?

F orthogonal decomposition, horizontal to the right is f1 = f*cos37 = 48n vertical upward f2 = f*sin37 = 36n

The pressure of the object on the ground is f3 = g - f2 = 100-36 = 64n if the object is moving, then the dynamic friction force f4 = f3 * , uniform straight line:

f-combined=f1-f4=0 f3* =f1 64* =48 = f-combined=ma=f1-f4, which can only be calculated if it is accelerating.

If it is stationary, the net force is 0 and cannot be calculated