Math Problem Statement

place three decimal places

Two cables tied together at C are loaded as shown. Knowing that the maximum allowable tension is 1,200N in cable AC and 600N in cable BC, determine: A) The magnitude of the largest force P that can be applied at C, B) The corresponding value of α.

Solution

To solve the problem, we need to consider the equilibrium of forces at point C. The forces acting at point C are the tensions in cables ACAC and BCBC, and the applied force PP at angle α\alpha.

Step 1: Analyze the forces

The tensions TACT_{AC} and TBCT_{BC} have maximum values of 1200 N and 600 N, respectively. The angles for these tensions relative to the horizontal are given as:

  • θAC=35\theta_{AC} = 35^\circ
  • θBC=50\theta_{BC} = 50^\circ

Step 2: Set up the equilibrium equations

For static equilibrium, the sum of forces in both the horizontal (xx) and vertical (yy) directions must be zero:

Horizontal Direction (xx-axis):

TACcos(35)+TBCcos(50)=Pcos(α)T_{AC} \cos(35^\circ) + T_{BC} \cos(50^\circ) = P \cos(\alpha)

Vertical Direction (yy-axis):

TACsin(35)+TBCsin(50)=Psin(α)T_{AC} \sin(35^\circ) + T_{BC} \sin(50^\circ) = P \sin(\alpha)

Step 3: Substitute maximum tensions

Given:

  • TAC=1200NT_{AC} = 1200 \, \text{N}
  • TBC=600NT_{BC} = 600 \, \text{N}

Substituting these into the equations:

Horizontal Direction:

1200cos(35)+600cos(50)=Pcos(α)1200 \cos(35^\circ) + 600 \cos(50^\circ) = P \cos(\alpha)

Vertical Direction:

1200sin(35)+600sin(50)=Psin(α)1200 \sin(35^\circ) + 600 \sin(50^\circ) = P \sin(\alpha)

Step 4: Solve for PP and α\alpha

To find PP and α\alpha, you divide the vertical equilibrium equation by the horizontal equilibrium equation:

tan(α)=1200sin(35)+600sin(50)1200cos(35)+600cos(50)\tan(\alpha) = \frac{1200 \sin(35^\circ) + 600 \sin(50^\circ)}{1200 \cos(35^\circ) + 600 \cos(50^\circ)}

Solving for α\alpha:

α=tan1(1200sin(35)+600sin(50)1200cos(35)+600cos(50))\alpha = \tan^{-1}\left(\frac{1200 \sin(35^\circ) + 600 \sin(50^\circ)}{1200 \cos(35^\circ) + 600 \cos(50^\circ)}\right)

Finally, substitute α\alpha back into either the horizontal or vertical equation to find PP.

Let's calculate these values.

Calculation

  1. Calculate tan(α)\tan(\alpha):

    tan(α)=1200×0.5736+600×0.76601200×0.8192+600×0.6428\tan(\alpha) = \frac{1200 \times 0.5736 + 600 \times 0.7660}{1200 \times 0.8192 + 600 \times 0.6428}

  2. Solve for α\alpha:

    α=tan1(0.651)\alpha = \tan^{-1}(0.651)

  3. Find PP:

    Use the horizontal equation to find PP:

    P=1200×0.8192+600×0.6428cos(α)P = \frac{1200 \times 0.8192 + 600 \times 0.6428}{\cos(\alpha)}

Let's calculate these values numerically.The calculations yield the following results:

  • Angle α\alpha: 39.98739.987^\circ
  • Magnitude of the largest force PP: 1786.318N1786.318 \, \text{N}

These are the values for the largest force PP that can be applied at point CC, and the corresponding angle α\alpha.

Do you have any questions or would you like more details on any part of this solution?

Here are some related questions you might explore:

  1. How would the results change if the tension in cable BCBC was increased to 800 N?
  2. What would be the effect on PP if α\alpha was set to 4545^\circ from the beginning?
  3. How does the system behave if the angle of TACT_{AC} was reduced by 55^\circ?
  4. What if the tension in cable ACAC were reduced by 200N200 \, \text{N}? What would happen to PP?
  5. How can this analysis be adapted if cable BCBC was at a different angle, say 4040^\circ?

Tip: When dealing with equilibrium problems, always ensure all force components are resolved correctly into horizontal and vertical components before applying equilibrium equations.

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Math Problem Analysis

Mathematical Concepts

Statics
Force Equilibrium
Trigonometry

Formulas

Sum of forces in the x-direction: ΣF_x = 0
Sum of forces in the y-direction: ΣF_y = 0
P = T_AC * cos(θ_AC) + T_BC * cos(θ_BC)
tan(α) = (T_AC * sin(θ_AC) + T_BC * sin(θ_BC)) / (T_AC * cos(θ_AC) + T_BC * cos(θ_BC))

Theorems

Equilibrium of Forces

Suitable Grade Level

College Level (Engineering Statics)