When winter comes, Xiao Ming, a senior one student, imagines installing a door curtain for the street room facing north at home. As shown in figure 1, he designed the hanging diagram of the door curta

When winter comes, Xiao Ming, a senior one student, imagines installing a door curtain for the street room facing north at home. As shown in figure 1, he designed the hanging diagram of the door curtain. (1) For the stress analysis of C in figure 1, as shown in the left figure, a rectangular coordinate system is established, and it can be known from the geometric relationship that △ACB is a regular triangle.

The angle between AC and BC and Y axis is 30, and the tension of ropes AC and BC is equal.

C in the vertical direction of the equilibrium state, 2F pulls cos30 =mg.

de:F = mg 2 cos 30 = 102×32 = 1033n？

(2) Analyze the stress in Figure 2 C, establish a rectangular coordinate system, and know from the geometric relationship that ∠ BAC = 37.

Establish an equilibrium equation, the vertical direction: F-pull +F-pull sin37 =mg?

Get: f tension = 6.25 n.

Horizontal direction: f pull cos37 =F F f.

Get: F=5N.

Answer: (1) Now let the door curtain hang in the air, as shown in figure 1, and the tension in the rope is1033 n;

(2) If the customer pushes the door curtain with horizontal thrust F, it is simplified as C just hangs below the B end at this time, BC = 3 cm, as shown in Figure 2. In this state, the Zhang Liwei in the rope is 6.25N and the horizontal thrust F is 5 N. 。