The principle of the gravitational constant was determined by the torsion scale experiment

British Franken Jerk Cavendish used his invention of the torsion scale in 1789 to verify the correctness of Newton's law of gravitation, and measured the gravitational constant, Cavendish experimental results and modern measurements are very close, it makes the law of gravitation have real practical value, Cavendish is also known as the first "person who can weigh the mass of the earth".

Another of Newton's great contributions was his law of gravitation, but how big is gravitation?

At the end of the 18th century, the English scientist Henry Cavendish decided to find out this gravitational force. He tied small metal balls to the sides of a 6-foot (1-foot-meter-long) stick and suspended it with a metal wire that resembled a dumbbell. Place two more 350-pound (1 pound equals kilogram) copper balls fairly close together to create enough gravitational pull for the dumbbell to turn and twist the wire.

The tiny rotations are then measured with a homemade instrument. The measurements were surprisingly accurate, and he measured the parameters of the gravitational constant, which is about g= (n·m 2 kg 2), usually taken as g =, on the basis of which Cavendish calculates the density and mass of the earth. Cavendish calculated that the mass of the Earth was x10 24kg.

1. Your guess is correct, the torsional force f=k is the angle at which the swing turns, and k is the torsion coefficient.

2. Experimental device: In a cylindrical glass cylinder, hang a button. The upper end of the twisted wire is suspended from the top of the cylinder, and the lower end is hung with a lightweight insulating rod with metal balls of the same quality at each end of the rod.

Not far from the metal ball near one end, place another metal ball. The gravitational force between them can be known based on the angle of torsion. I don't remember the specifics either, you can check it yourself, there should be.

3. The K principle of the Coulomb test is similar to the G principle of the Cavendish test, except that one side of the insulating rod hanging under it is an insulating item, and the other side is an item that can be carried. Fixing a dotted object, allowing the dotable object to come into contact with it, and dividing the charge equally, produces the Coulomb repulsion.

4. However, the latter is much more demanding. Here's why:

There is a gravitational force between any two objects on Earth, however, you can barely see it. The quality of the ball used by Cavendish is not very large, so the fineness of the twist is required.

Torsion scale experiment: It is a scientific experiment of mechanics.

According to Newton's law of gravitation, Cavendish measured the gravitational front constant g by torsion scale solid chain dismantling, and this experiment has nothing to do with the radius of the earth, the mass of the sun, and the distance from the earth to the sun

In the history of our country, there has been a story of Cao Chong calling the elephant, and this staring is already a household name. The clever Cao Chong used a clever method to weigh the elephant.

But if you want to "weigh" the weight of the earth, how can you "weigh"?! With such a large earth, it is impossible to imagine that there is no one or any instrument that can weigh the earth on the scales, and there is no scale in the world that can accommodate the earth!

More than 200 years ago, the British physicist Henry Cavendish had already called the earth. He didn't use a fiber scale, but calculated it according to Newton's law of gravitation. According to this law, there is a gravitational interaction between the planets in the universe, including the Earth.

The heavier the weight and the closer the distance, the greater the gravitational pull, and conversely, the lighter the weight, the less the gravitational pull.

He built a device shaped like a dumbbell, hung it on a filament, and then placed a large ball of known weight at each end of the "dumbbell" at a certain distance, measured the force of attraction between them, calculated the gravitational constant, and found the average density of the earth in grams (centimeters)3.

Then according to the circumference, diameter and other parameters of the earth, the volume of the earth is calculated to be 1,083 billion cubic kilometers, and the product of density and volume is the weight of the earth, and the calculation result is 66 trillion tons, which is the famous "twist test".

Scientists have calculated the weight of the earth more scientifically through modern precision instruments, and the result is a trillion tons, which is a trillion tons less than the "twisted weighing test".

Torsion scale is the first digging brother test: it is a kind of scientific dispersion experiment of the first attack mechanics.

In the early days of physics, it was difficult to measure weak effects because they were often not felt. Later, physicists came up with the idea that it would take a lot of force to break a wire, and to twist a wire, it would be possible to do it with a small force. Based on this assumption, the French physicist Coulomb and the British Frankendrin Jaca Vendish independently invented the torsion scale in 1785 and 1789, respectively.

The key is that it amplifies the weak effect of the micro and Zen dust, and the key is that it amplifies the weak effect twice: on the one hand, the small force can produce a large moment through the longer force arm, so that the suspension wire can produce a certain angle of torsion of the shed limb; On the other hand, a plane mirror is fixed on the suspensory, which can reflect the incident light onto the scale that is far away from the plane mirror, and the slight twisting of the suspensory can be shown from the movement of the reflected light rays to the light point on the scale.

Did you learn torque?

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The experimental questions of college physics will only be tested for this, and you can rest assured that you will not be able to take the college entrance examination, and this formula is simplified.

Eggplant invented the torsion scale to determine the gravitational constant g.

a.Gatrem next to molvanide.

b.Voltaic. c.Cavendish Sh.

d.Edison Begins Sleepy.

Correct answer: c