I am having some trouble with the following passage in section4.2 of vol. I of the Feynman Lectures on Physics:

A very simple weight-lifting is shown in Fig. 4-1. This machine lifts three units "strong". We place three units on one balance pan, and one unit on the other. However, in order to get it actually to work, we must lift a little weight off the left pan. On the other hand, we could lift a one-unit weight by lowering the three-unit weight, if we cheat a little by lifting a little weight off the other pan.

^{Figure 4.1}

The highlighted sentence feels superfluous. I understand that he wanted to avoid using specific units of measurement, but why is the machine presented as one that only lifts three units when just a couple of sentences later, the same machine is said to lift one unit and lower the three units? Why not say "this machine is a see-saw"?

I am having some trouble with the following passage in section 4.2 of vol. I of the Feynman Lectures on Physics:

A very simple weight-lifting is shown in Fig. 4-1. This machine lifts three units "strong". We place three units on one balance pan, and one unit on the other. However, in order to get it actually to work, we must lift a little weight off the left pan. On the other hand, we could lift a one-unit weight by lowering the three-unit weight, if we cheat a little by lifting a little weight off the other pan.

^{Figure 4.1}

The highlighted sentence feels superfluous. I understand that he wanted to avoid using specific units of measurement, but why is the machine presented as one that only lifts three units when just a couple of sentences later, the same machine is said to lift one unit and lower the three units? Why not say "this machine is a see-saw"?

FLCH42 stands for Feynman Lectures Chapter 4.2, known to frequently confuse budding physicists. This is the second in a personal series of questions I had about the chapter.

Excerpt:

A very simple weight-lifting is shown in Fig. 4-1. This machine lifts three units "strong". We place three units on one balance pan, and one unit on the other. However, in order to get it actually to work, we must lift a little weight off the left pan. On the other hand, we could lift a one-unit weight by lowering the three-unit weight, if we cheat a little by lifting a little weight off the other pan.

Figure 4.1:

The highlighted sentence feels superfluous. I understand that he wanted to avoid using specific units of measurement, but why is the machine presented as one that only lifts three units when just a couple of sentences later, the same machine is said to lift one unit and lower the three units? Why not say "this machine is a see-saw"?

I am having some trouble with the following passage in section4.2 of vol. I of the Feynman Lectures on Physics:

A very simple weight-lifting is shown in Fig. 4-1. This machine lifts three units "strong". We place three units on one balance pan, and one unit on the other. However, in order to get it actually to work, we must lift a little weight off the left pan. On the other hand, we could lift a one-unit weight by lowering the three-unit weight, if we cheat a little by lifting a little weight off the other pan.

^{Figure 4.1}

The highlighted sentence feels superfluous. I understand that he wanted to avoid using specific units of measurement, but why is the machine presented as one that only lifts three units when just a couple of sentences later, the same machine is said to lift one unit and lower the three units? Why not say "this machine is a see-saw"?