Math Problem Statement

Find the values of P and Q from the given forces in equilibrium with angles 49° and 18°.

Solution

To solve for the values of PP and QQ in this equilibrium problem, we need to apply the conditions for equilibrium. The forces are balanced, meaning both the horizontal and vertical components of the forces must sum to zero.

Step 1: Resolve the forces into components

The given forces are:

  • A force of 10 N at an angle of 49° above the horizontal.
  • Forces PP and QQ, whose directions are given as vertical and angled 18° below the horizontal, respectively.

Force Components:

  • 10 N Force:

    • Horizontal component: 10cos(49)10 \cos(49^\circ)
    • Vertical component: 10sin(49)10 \sin(49^\circ)
  • Force QQ (angled at 18° below the horizontal):

    • Horizontal component: Qcos(18)Q \cos(18^\circ)
    • Vertical component: Qsin(18)Q \sin(18^\circ)
  • Force PP is purely vertical, so it only has a vertical component PP.

Step 2: Set up equilibrium conditions

Horizontal equilibrium:

Since the system is in equilibrium, the sum of horizontal forces must be zero: 10cos(49)=Qcos(18)10 \cos(49^\circ) = Q \cos(18^\circ) From this, we can solve for QQ: Q=10cos(49)cos(18)Q = \frac{10 \cos(49^\circ)}{\cos(18^\circ)}

Vertical equilibrium:

The sum of the vertical forces must also be zero: P+Qsin(18)=10sin(49)P + Q \sin(18^\circ) = 10 \sin(49^\circ) We can rearrange this to solve for PP: P=10sin(49)Qsin(18)P = 10 \sin(49^\circ) - Q \sin(18^\circ)

Step 3: Calculation

Using the known trigonometric values:

  • cos(49)0.6561\cos(49^\circ) \approx 0.6561
  • sin(49)0.7547\sin(49^\circ) \approx 0.7547
  • cos(18)0.9511\cos(18^\circ) \approx 0.9511
  • sin(18)0.3090\sin(18^\circ) \approx 0.3090

Solving for QQ:

Q=10×0.65610.95116.90NQ = \frac{10 \times 0.6561}{0.9511} \approx 6.90 \, \text{N}

Solving for PP:

P=10×0.75476.90×0.30907.552.13=5.42NP = 10 \times 0.7547 - 6.90 \times 0.3090 \approx 7.55 - 2.13 = 5.42 \, \text{N}

Final Answer:

  • Q=6.9NQ = 6.9 \, \text{N}
  • P=5.4NP = 5.4 \, \text{N}

Would you like a detailed explanation of the steps or any clarifications?

Here are 5 follow-up questions:

  1. What happens if the angle of force QQ is changed?
  2. How do we solve for forces in non-equilibrium cases?
  3. Can this method be used for three-dimensional force problems?
  4. How do the trigonometric identities simplify force resolution?
  5. What happens if one of the forces is doubled?

Tip: Always break forces into their components when dealing with equilibrium problems involving angled forces.

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Math Problem Analysis

Mathematical Concepts

Force Equilibrium
Trigonometry

Formulas

Horizontal equilibrium: 10 * cos(49°) = Q * cos(18°)
Vertical equilibrium: P + Q * sin(18°) = 10 * sin(49°)

Theorems

Conditions of Equilibrium
Resolution of Forces

Suitable Grade Level

Grades 10-12