Question

Обрыв. Концы однородного стержня длины L = 100 см привязаны к гвоздю нитями длины Li =60 см и L2 = 80 см. При каком весе стержня произойдёт обрыв, если нити рвутся при натяжении Т 220 Н? Нити невесомы и нерастяжимы.

Answer 1

Ответ:100

Объяснение:

Answer 2

Problem Analysis

We have a homogeneous rod of length L = 100 cm, with its ends tied to nails using strings of lengths Li = 60 cm and L2 = 80 cm. The strings can withstand a tension of T = 220 N before breaking. We need to determine the weight of the rod at which it will break.

Solution

To solve this problem, we need to consider the forces acting on the rod and the tension in the strings.

Let's assume the weight of the rod is W. The forces acting on the rod are the tension forces in the strings and the weight of the rod itself.

1. Tension in string 1 (T1): - The tension in string 1 can be calculated using the equation T1 = W * (L1 / L), where L1 is the length of string 1. - Substituting the given values, we have T1 = W * (60 cm / 100 cm).

2. Tension in string 2 (T2): - The tension in string 2 can be calculated using the equation T2 = W * (L2 / L), where L2 is the length of string 2. - Substituting the given values, we have T2 = W * (80 cm / 100 cm).

3. Equating the sum of the tensions in the strings to the breaking tension T: - T1 + T2 = T - W * (60 cm / 100 cm) + W * (80 cm / 100 cm) = 220 N

To find the weight of the rod (W), we can solve the equation above.

Calculation

Let's solve the equation to find the weight of the rod:

W * (60 cm / 100 cm) + W * (80 cm / 100 cm) = 220 N

Simplifying the equation:

0.6W + 0.8W = 220 N 1.4W = 220 N W = 220 N / 1.4 W ≈ 157.14 N

Answer

The weight of the rod at which it will break is approximately 157.14 N.

Please note that the above calculation assumes ideal conditions and neglects any other factors that may affect the breaking point of the rod.