Sitting closer to the fulcrum when playing seesaw?

The closer you are to the fulcrum, the shorter the moment, and the greater the force required to lift the person on the other side of the seesaw.

Do you remember the basics of physics you learned in junior high school? Those who know about force, electricity, light, sound, electromagnetism, power. If none of this can be remembered, let alone Ohm's law, Newtonian mechanics, Maxwell's theory of electromagnetism, Joule's law, conservation of energy, the nature of light, and modern quantum physics.

It is estimated that many people's knowledge of physics is also obtained through painful struggles. In addition to Xueba, seeing the following pictures, who has not doubted life, why should they learn this kind of thing?

Time precipitation, thinking maturity, when we have done a good job of returning physics knowledge, we realize the value of basic disciplines. I didn't understand the beauty of physics when I was young, and I was middle-aged when I read it.

Recently, I was watching "Does God Roll the Dice?" It re-understands the great process of human understanding of the world. I am already raising children today, and I especially hope to tell my children about the things I didn't do well, the detours I have taken, and the beauty I missed.

For example, to understand the profundity of physics, to better understand the world we live in. How to stimulate children's enthusiasm for physics, so that they will not relax the study of basic subjects because of complex and boring test-taking education, is a very important issue.

Whether it is artificial intelligence or quantum communication, it needs strong support from basic disciplines such as mathematics and physics. The reason why we lack major original scientific research achievements is that we are stuck in basic disciplines. ”

As parents, we can't replace our children in physics, but we can help our children make some improvements so that the learning process is no longer as boring as when we were younger.

The fulcrum, resistance point and force point of the seesaw are analyzed as follows:

The five elements of leverage.

Fulcrum: The point at which the lever turns, usually denoted by the letter O.

Power: The force that turns a lever, usually expressed as f1.

Resistance point: The force that prevents the lever from turning, usually expressed as f2.

Power point: The distance from the fulcrum to the line of action of the force, usually denoted by L1.

Resistance arm: The distance from the fulcrum to the line of action of resistance, usually denoted by L2.

Note: The dynamic action line, the resistance action line, the power arm and the resistance arm are all represented by dotted lines. The lower corner mark of the force arm changes with the lower corner mark of the force. For example, if the power is F3, the power arm is L3; The resistance is F5 and the resistance arm is L5）

The place where the two of them sit is the power point and the resistance point (any writing, indistinguishable), and the pillar in the middle is the fulcrum.

Put you up, your side is the force point, and the other party is the resistance point for you, so the other side is the resistance point.

For the seesaw to be balanced, the equilibrium condition of the lever must be satisfied, i.e., f1 l1 = f2 l2;

That is, m1 gl1 = m2 gl2, if the masses of the two children are not equal, then the distance from the two children to the fulcrum is not equal; If the masses of the two children are equal, the distance from the fulcrum is equal for the two children

So the answer is: not necessarily; f1 l1 =f2 l2 ．

It turns out that the leverage is balanced, so g big l big = g small l small;

The two move away from the fulcrum at the same time at an equal speed, so that the force arms on both sides are increased, and l is equal;

Then the adult side: g large (l large + l) = g large l large + g large l child side: g small (l small + l) = g small l small l small l g large l large l large = g small l small; And g big g small, g big l big + g big l g small l small l small + g small l, the seesaw is tilted to the adult side, that is, the adult side sinks, b is correct, acd is wrong

Therefore, choose B