Question

Алюминиевый ящик кубической формы весит 20 Н. Длина ребра ящика составляет 20 см. Какова толщина стенок такого ящика? Прими g равным 10 Н/кг. Вырази ответ в см и округли до десятых. ФИЗИКА 7 КЛАСС , СРОЧНО!!!!ДАЮ 50 БАЛЛОВ

Answer 1

Ответ:3,5 мм

Объяснение:

Answer 2

Calculating the Thickness of the Aluminum Box

To calculate the thickness of the walls of the aluminum box, we can use the formula for weight:

Weight = Mass × Acceleration due to gravity

Given: - Weight (W) = 20 N - Acceleration due to gravity (g) = 10 N/kg - Length of the side of the cube (l) = 20 cm

First, we need to find the mass of the aluminum box using the weight and the acceleration due to gravity:

Mass = Weight / Acceleration due to gravity

Mass = 20 N / 10 N/kg = 2 kg

The mass of the aluminum box is 2 kg.

Next, we can calculate the volume of the cube using the length of the side:

Volume = (Length of side)^3

Volume = (20 cm)^3 = 8000 cm^3

Since the box is a cube, the volume is the same as the internal volume of the box.

Now, we can calculate the volume of the aluminum used in the box. Since the box is hollow, the volume of the aluminum used is the difference between the external volume and the internal volume.

Let's assume the thickness of the walls is "t" cm.

External Volume = (Length of side + 2t)^3

Internal Volume = (Length of side)^3

Volume of Aluminum = External Volume - Internal Volume

8000 cm^3 = (20 cm + 2t)^3 - (20 cm)^3

Solving for "t" will give us the thickness of the walls of the aluminum box.

Let's calculate the value of "t" using the given information and the formula.

Calculation

8000 cm^3 = (20 cm + 2t)^3 - (20 cm)^3

8000 cm^3 = (20 cm + 2t)^3 - 8000 cm^3

16000 cm^3 = (20 cm + 2t)^3

Taking the cube root of both sides:

(20 cm + 2t) = (16000 cm^3)^(1/3)

20 cm + 2t = 25.368 cm

2t = 25.368 cm - 20 cm

2t = 5.368 cm

t = 5.368 cm / 2

t ≈ 2.684 cm

Answer

The approximate thickness of the walls of the aluminum box is 2.7 cm (rounded to the nearest tenth).