Seeing that many friends are puzzled about why carrying a thousand pounds of heavy stones in chapter 21 can be faster, and even laughing at the physical common sense of the house pig, the house pig feels the need to explain.

Many people know that many people know that two iron balls, one large and one small, fell from the leaning tower at the same time and landed at the same time, some people say that it is in the primary school textbook, but the primary school textbook does not talk about the knowledge of junior high school, that is, wind resistance and air buoyancy.

Air buoyancy is very small, but it also has an effect on larger objects, in addition to the biggest impact on the speed of gravitational acceleration is air resistance, wind resistance.

When a person falls from a height, the wind resistance will cancel out the acceleration and make the fall speed reach a fixed value, which is 25 to 50 meters per second, and cannot exceed this speed.

The density of the stone is seven times that of the human body, the potential energy is greater, and the effect of wind resistance is less, so the speed can be faster.

So, is Galileo's Leaning Tower test correct, who is faster when two iron balls, one large and one small, fall at the same height?

Let's use junior high school physics to do the math.

If two round stones are one large and one small, the air resistance Fw=1/16・A・Cw・v^2 is set to CW=1, A1=1, A2=r^2, and the mass m1=1,m=r^3.r>1, then the air resistance FW1=1/16*V1^2FW2=1/16*V2^2*r^2

Gravity: G1=g, G2=r^3*g

1. If the velocity is the same, the acceleration a1=(g-1/16*v^2), a2=(r^3*g-1/16*v^2*r^2)/r^3=(g-1/16*v^2*1/r)>a1a2>a1, and the acceleration of large stones is fast.

2. When the ultimate speed is reached, the speed does not increase. Then 1/16*v1^2=g, 1/16*v2^2*r^2=r^3*g, 1/16*v2^2=r*g, V2>V1, the final velocity of the uniform motion of the iron ball is large. So the big iron ball landed first.

3. It is more difficult to calculate in the case of calculating air buoyancy, but there is a simple way to test it, in water. Water also has buoyancy, take an iron ball and a piece of meat, fall into the water, and see who lands first. Obviously, the iron ball landed first.

A similar test can also be used, that is, an ant and an ant lying on a stone fall from the air at the same time, the same height, which one lands first?

If you still have doubts about this, go to junior high school physics, calculate more, and don't take it for granted.