Help me solve a physical science problem! 10

Select A when the light does not glow, the switch is disconnected, and the indicator light glows at this time;

When the light is illuminated, the switch is closed, and the indicator light does not light at this time.

As inferred from the above, either the switch is a single pole double throw or the switch is connected in parallel with the indicator (in this case, when the indicator light is illuminated, it is connected in series with the light and causes the light to also light up). The visible switch should be a single pole double throw with the indicator in parallel with the illuminator.

The answer is probably d!

Use a single-pole and double-position switch to control the circuit, and the switch is connected in series with the indicator light when it is dialed up; When the switch is flipped down, it is connected in series with the light.

It's just that I think something is slightly inappropriate is that the indicator light has a faint light when the light is not on. According to my thoughts, all voltages are added to the indicator light, so it shouldn't be considered a faint light!

There's only so much I can explain, I haven't learned circuits for a long time, think about it yourself!

C should be selected because the switch is connected to the live wire before connecting the light, and the switch is connected in parallel with the indicator light, the switch is turned on, the indicator light is short-circuited, and the indicator light is on and the indicator light is off. The switch is off, and the two lights form a path, but the resistance of the indicator light is large, and the voltage is large, and the light is not on.

c.When the switch is closed, the current flows to the switch and not to the electrical indicator. This causes the light to turn on and the indicator to short-circuit. When the switch is disconnected, the indicator light forms a series circuit with the circuit, and all the voltage is given to the indicator light, so it is on and the light is off.

Choose a because after the light goes out, the indicator light works, so it does not affect each other, and it is in parallel.

So A is absolutely right.

So if it's a multiple-choice question, choose A.

My answer is simple and easy to understand.

Definitely choose C

When the switch is disconnected, the voltage drop falls on the indicator light, making the indicator light on; The switch is closed, the short-circuit indicator is turned on, and the light is turned on to glow.

1. The volume of aluminum v = m p = 3rd power = cubic meter.

The side length of aluminum is a = meter.

The contact area between the aluminum and the table is s = square meters.

The gravitational force of aluminium g=mg=

Let the vertical upward tension of the aluminum block be f, and the pressure of the table top p=(g-f) s

1000=（27-f）/

f = 37n2, the total gravity of the goods and the pine g = mg = (700 + 20) x 10 = 7200n The volume of pine is v = 20 to the 3rd power = cubic meter.

So people can pull the planks and carry these goods safely across the river.

"If the maximum pressure that the ice surface can withstand is 7x10 to the 4th power," it is 7x10 to the 3rd power.

Check the corrections yourself. The method is fine.

Please click to adopt, and ask if you don't know.

1.The pressure is calculated from the pressure, and then according to the equilibrium equation, the tensile force ff=mg-ps s can be obtained from the mass density to get the volume, because it is a cube, the side length can be calculated, and then the base area s can be calculated

2.The total pressure p is calculated in the same way, (mg+700*g) s=p If p>7x10 to the 4th power of Pa, then it cannot be safely transported across the river.

If p is less than or equal to 7x10 to the 4th power of the PA, then it can be safely transported across the river S can calculate the volume according to the mass density (of 3), and then the volume thickness (5cm) to obtain the bottom area S

Then it's okay to substitute the data.

.Don't forget it. That's the way it works.

1. From the density formula, it can be seen that v=m, then the volume of the aluminum block is 10-3 cubic meters, that is, the bottom area of the aluminum block is, and the pressure formula can be known f=ps, when the desktop pressure is 1000pa, it is equivalent to the pressure generated by the pressure of 10N, and the gravity of the aluminum is 27N (g takes 10N kg), indicating that the aluminum block is also subjected to an upward tensile force of 17N.

2. From the density formula, it can be known: v=m, then the volume of the wooden block is cubic meters, and the height of the wooden block is known by v=sh, the area of pine is 1 square meter, and the weight of the goods plus pine is 720kg, that is, the gravity is 7200N, and the pressure generated by the pressure formula p=f s can be known that the pressure generated by it is 7200pa, which is obviously less than 7x10 to the 4th power of PA so it can be safely crossed the river, as for the gravity of people, people are not stepping on pine, so the pressure of pine on the ice does not need to consider human gravity, From the point of view of independent effect, the ice surface can withstand the pressure of people, as well as the pressure of objects and pine trees, so people can safely transport these goods across the river by pulling the planks.

Selected equipment: spring dynamometer, plasticine, fine wire.

**Steps: 1. Tie the plasticine with a thin wire, measure its gravity with a spring dynamometer, record the data 2, change the shape of the plasticine, and repeat step 1

3. Repeat the above experiment.

Analysis: If the results of the three recordings are different, gravity is related to shape. If the result of the three recordings is the same, then the gravity is independent of the shape.

Can you talk, it's too troublesome, just tell you about it.

First of all, the height of *** is a variable proportional to the 3rd power of t, and it can be seen that the initial velocity of the package in the vertical direction is not zero. This velocity must be calculated, combined with its free fall motion, the initial vertical direction of the fierce velocity, and the height of the throwing solution, the slag quickly out of the landing, as if it takes time. h=，v=-h'=。

Initial height h0=; Vertical velocity v0=.

h=v0t+1 2at, substitution, the solution obtained by solving this equation is the time required. If I'm not mistaken, t=, the other is negative, discarded.

q=qv=

m=q/q=

Equivalent to burning coke.

u = u2 - u1 = 20 - 15 = 5 vi = i2 - i1 = 0. 5 a

r = u stupidity δi = 5 = 10 p1 = u1 * u1 r = 15 * 15 10 = w

p2 = u2 * u2 / r = 20 * 20 / 10 = 40 w

p = p2 - p1 = 40 - = w Answer: The power booth has added tiled halls.

From the meaning of the title: u1 r1-u2 r2=δi

That is, 20 permeable large fiber boy r1-15 r1=,,r1=10p=u2 2 r1-u1 2 r1=

This was increased by the cluster.

According to the title, Huai Pai Sen has 20 r1-15 r1 = and gets r1 = 10 ohms, then the increase of the power is 20 10-15 lead mu 10 = watts.