20 drawing circuit diagram, 20 physical pictures, 50 questions, OK, give you 20 to 100 points

Do you think it's ok

Bulbs L1 and L2 are connected in series in the circuit. The resistance of L1 is greater than that of L2. In the same time, the current does work through the bulb ()
A. L1 lamp does more work B. L2 lamp does more work C. two lamps do the same amount D. unable to judge

Because the bulbs L1 and L2 are connected in series in the circuit, the current through the two lamps is equal, and the resistance of L1 is larger than L2. According to P = I2R, the power of L1 is larger than L2. According to w = Pt, the current through the bulb L1 does more work in the same time

What are the three elements of force
barring
A. Direction
B. Action point
C. Size
D. Mode

Excluding D. mode

Xiaoyu pulled a stone with a rope to make it rotate at a constant speed on the horizontal plane. He thought that if the force on the stone disappeared, the stone would ()
A. Stop the movement immediately. B. fall to the ground. C. continue to rotate at a constant speed. D. do a straight line movement at a constant speed

Because the original state of the object is moving, when the force on the stone disappears at the same time (the resultant force is zero), the stone should keep its original speed and move in a straight line at a constant speed

When the temperature of 1.1kg water increases by 1 ℃, the heat absorbed is 4.2x10 cubic coke, and the heat of 2.1x10 quartic coke can increase the temperature of several thousand grams of water by 1 ℃, while releasing 4.2x10 quintic coke can reduce the temperature of 1kg water by several ℃
2. In winter in northern China, the indoor heating uses hot water circulation instead of other liquids. What is the reason: when the same temperature is lowered, the heat released by water is higher than that of other liquids of the same quality——

1. The specific heat capacity of water is 4.2x10 & sup3; J / (kg ·℃);
(1) From q = cm Δ T, M = q / C Δ t = 2.1x10 * 4J / 4.2x10 & sup3; J / (kg ·℃) x1 ℃ = 5kg
(2) From q = cm Δ T, Δ t = q / cm = 4.2x10 * 5J / 4.2x10 & sup3; J / (kg ·℃) x1kg = 100 ℃
2. Because the specific heat capacity of water is relatively large, when lowering the same temperature, water releases more heat than other liquids of equal mass

(1) Please give three examples of urban noise
(2) Please talk about the harm of urban noise
(3) Please talk about the measures to prevent and control urban noise

(1) The first is the noise produced by cars in traffic; the second is the noise produced by construction sites in the city; the third is the noise produced by music played in commercial places (2) · hearing damage. Some tests show that when people listen to motorcycles continuously, their hearing will be damaged after 8 hours; if they are in a rock concert hall, their hearing will be damaged after half an hour

Please give an example of industrial noise and a case of traffic noise

Industrial noise: construction site construction noise
Traffic noise: Car whistle

It's noisy
Many measures have been taken to control the noise in the city
1. No fireworks in urban areas:__________________
2. Afforestation:_
3. Installation of sound insulation wall:__
4. Workers wearing earmuffs on construction site:_
5. No honking in urban area:__________________

1. No fireworks in urban area: at the sound source
2. Afforestation:
3. Installation of sound insulation wall:
4. Workers wear earmuffs at the construction site: sound receiving place
5. No honking in urban area: where is the sound source

The installation of sound absorbing material around the source is one of the common methods to control noise. In the two materials of sponge and foam plastics, who has better sound absorption effect? Please design an experiment to answer this question.
(1) Write down the main equipment used in the experiment
(2) Brief introduction of the experimental process
(3) In order to get accurate and reliable conclusions, we should control which factors are the same and compare which phenomena
Brothers and sisters, I beg you!

answer: (1) equipment: sound source (such as alarm clock, radio, etc.), sponge, foam plastic, fine thread or tape paper.
(2) the experiment process: turn on the radio, wrap the radio with sponge and foam plastic respectively, compare the difference of loudness heard in two cases.
(3) The thickness of the two materials, the way of wrapping the radio, the volume (loudness) of the radio and the distance between the listener and the radio (alarm clock) should be kept the same. Then we can draw a conclusion by comparing the size of the sound (loudness)
[solutions]
They are used to eliminate sound. When sound enters these objects, it will be reflected many times until it disappears

Scientists suggest not to sweep all the fallen leaves. What do you think is the reason?
Through experiments, scientists have proved that 40m wide forest belt can reduce noise by 15db-30db

Fallen leaves on the ground will change the sound transmission path, in the process of change, the sound is constantly absorbed, thus reducing the harm of noise to human body

20 drawing circuit diagram, 20 physical pictures, 50 questions, OK, give you 20 to 100 points