# Prof. Walter Lewin Explains "That's that rho of s

• anhnha
In summary, Prof. Walter Lewin discusses the concept of rho of s in relation to the voltage wave passing through two wires, wire 1 and wire 2, in an electric field. He explains that rho of s refers to the positive and negative charges on the wires, and that the setup involves the two wires being connected to opposite terminals of a battery. This concept is discussed in his lecture starting around 8:30 and concluding around 9:30.

#### anhnha

Please help me. What does the Prof. Walter Lewin mean by this "that is that rho of s"?

If I take this wire and I make a cross-section of that wire-- this is wire 1 and this is wire 2-- then at any moment in time, as the voltage wave passes by, this may be positive, that is that rho of s, and this will be negative, that's that rho of s .

I think he starts talking about it around 8:30 and eventually makes his way to the right end of the board around 9:30. He has an electric field dependent on rho_s I think he meant "rho sub s" (rho with subscript s).

1 person
Thanks. Can you explain why the positive or negative of these wires are related to the rho of s?

Any help?

I don't remember the exact setup and currently on mobile, but I thought the setup was the two wires were each on opposite terminals of a battery, so you have a positive charge on one wire and a negative on the other.

## 1. What is "That's that rho of s"?

"That's that rho of s" is a phrase coined by Prof. Walter Lewin in his popular physics lectures at MIT. It refers to the mathematical symbol "ρ" (rho) which represents density, and "s" which represents position. This phrase is used to introduce the concept of density and its relationship to position in the context of physics problems.

## 2. Why does Prof. Walter Lewin use this phrase in his lectures?

Prof. Lewin uses this phrase to emphasize the importance of understanding the concept of density in physics problems. He often explains that density is a crucial factor in determining the behavior of objects, and by using this phrase, he aims to make it more memorable and relatable for his students.

## 3. What does "rho of s" mean in physics?

In physics, "rho of s" refers to the density of a material at a specific position. Density is defined as the mass of an object divided by its volume, and it is a measure of how tightly packed the particles of a substance are. By understanding the relationship between density and position, we can better understand the behavior of objects in different situations.

## 4. How does Prof. Walter Lewin explain "That's that rho of s" in his lectures?

Prof. Lewin typically explains "That's that rho of s" by using real-life examples and visual aids. He often demonstrates how the density of an object can change depending on its position, and how this affects its behavior. This helps students to understand the concept in a more practical and memorable way.

## 5. Is understanding "That's that rho of s" important for studying physics?

Yes, understanding "That's that rho of s" is crucial for studying physics. Density is a fundamental concept in physics, and it is used to explain various phenomena in the physical world. By understanding this concept, students can better understand the behavior of objects and solve physics problems more effectively.