Math Problem Statement

A simply supported beam is loaded with a vertical point load F2 and an inclined point load F1 at 60° to the beam's axis. Calculate: a) the total vertical force Fv, b) the vertical reaction forces at points A and B, and c) the horizontal reaction force at point B.

Solution

The problem you provided is about a simply supported beam under two forces, F1F_1 and F2F_2. Let's break down the steps to solve it.

Given:

  • F1=6kNF_1 = 6 \, \text{kN}, inclined at 60° to the horizontal axis.
  • F2=6kNF_2 = 6 \, \text{kN}, applied vertically downward.
  • Lengths of beam segments: 2.40m2.40 \, \text{m}, 1.70m1.70 \, \text{m}, and 4.40m4.40 \, \text{m}.
  • Total length of the beam = 2.40+1.70+4.40=8.50m2.40 + 1.70 + 4.40 = 8.50 \, \text{m}.
  • Supports at points A and B.

Tasks:

  1. Vertical force sum (FvF_v): You need to sum the vertical components of the applied forces.

    • The vertical component of F1F_1: F1v=F1sin(60)=6×sin(60)=6×0.866=5.196kNF_{1v} = F_1 \sin(60^\circ) = 6 \times \sin(60^\circ) = 6 \times 0.866 = 5.196 \, \text{kN}
    • The vertical component of F2F_2 is already vertical: F2v=6kNF_{2v} = 6 \, \text{kN}.

    Therefore, the total vertical force is: Fv=F1v+F2=5.196kN+6kN=11.196kNF_v = F_{1v} + F_2 = 5.196 \, \text{kN} + 6 \, \text{kN} = 11.196 \, \text{kN}

  2. Vertical reaction forces at A and B:

    • Let RAR_A and RBR_B be the reaction forces at points A and B, respectively.

    • To solve for these reaction forces, we apply the equilibrium conditions:

      Sum of vertical forces: RA+RB=Fv=11.196kNR_A + R_B = F_v = 11.196 \, \text{kN}

      Sum of moments about A: Moment at A=0=RB×8.50F1sin(60)×2.40F2×4.10\text{Moment at A} = 0 = R_B \times 8.50 - F_1 \sin(60^\circ) \times 2.40 - F_2 \times 4.10 Substituting values: RB×8.505.196×2.406×4.10=0R_B \times 8.50 - 5.196 \times 2.40 - 6 \times 4.10 = 0 Simplifying: 8.50RB=12.47+24.68.50 R_B = 12.47 + 24.6 8.50RB=37.07    RB=37.078.50=4.36kN8.50 R_B = 37.07 \implies R_B = \frac{37.07}{8.50} = 4.36 \, \text{kN}

      Now substitute RBR_B into the equation RA+RB=11.196R_A + R_B = 11.196: RA=11.1964.36=6.84kNR_A = 11.196 - 4.36 = 6.84 \, \text{kN}

  3. Horizontal reaction force at B:

    • Only the horizontal component of F1F_1 needs to be considered since F2F_2 is vertical.
    • The horizontal component of F1F_1 is: F1h=F1cos(60)=6×cos(60)=6×0.5=3kNF_{1h} = F_1 \cos(60^\circ) = 6 \times \cos(60^\circ) = 6 \times 0.5 = 3 \, \text{kN} Therefore, the horizontal reaction force at B must balance this force: RBh=F1h=3kNR_{Bh} = F_{1h} = 3 \, \text{kN}

Summary:

  • Fv=11.196kNF_v = 11.196 \, \text{kN}
  • RA=6.84kNR_A = 6.84 \, \text{kN}
  • RB=4.36kNR_B = 4.36 \, \text{kN}
  • Horizontal force at B=3kNB = 3 \, \text{kN}

Would you like any further details or clarifications?

Here are 5 related questions to further explore the topic:

  1. How would the solution change if the angle of F1F_1 were different?
  2. What would happen if the beam were supported at only one point?
  3. How do the moments of inertia affect beam deflection in this scenario?
  4. What would be the impact of a third force applied horizontally?
  5. How does the beam's material affect the reactions at supports?

Tip: When solving for reaction forces, always ensure to sum forces and moments to zero for a static system.

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Math Problem Analysis

Mathematical Concepts

Statics
Forces
Moments
Trigonometry

Formulas

Vertical component of force: Fv = F1 * sin(θ) + F2
Sum of moments: M_A = R_B * L - F1v * d1 - F2 * d2
Horizontal component of force: Fh = F1 * cos(θ)

Theorems

Equilibrium conditions
Sum of forces = 0
Sum of moments = 0

Suitable Grade Level

Undergraduate Engineering