Math Problem Statement

1 What is the reaction at point A?(2 Points) 9.69 kN 6.81 kN 7.80 kN 11.12 kN 2 What is the reaction at point E?(2 Points) 9.69 kN 6.81 kN 7.80 kN 11.12 kN 3 What is the summation of shear force at point B?(2 Points) 5.03 kN 4.23 kN 2.81 kN 3.92 kN 4 What is the summation of shear force at C?(2 Points) -2.19 kN -4.23 kN -3.57 kN 3.57 kN 5 What is the value of moment at point A?(2 Points) Zero 7.81 kN 5.71 kN 3.81 kN 6 What is the value of moment at point B?(2 Points) 13.62 kN 23 kN 11.53 kN 12 kN 7 Maximum moment is located at point(2 Points) B C D none of the above 8 The value of maximum moment is (2 Points) 20.17 kN-m 19.24 kN-m 17.17 kN-m 15.07 kN 9 The value of moment at point D is(2 Points) 19.24 kN 15.07 kN 14.86 kN 24.46 kN

What is the reaction at point A? What is the reaction at point E? What is the summation of shear force at point B? What is the summation of shear force at C? What is the value of moment at point A? What is the value of moment at point B? Maximum moment is located at point? The value of maximum moment is? The value of moment at point D is?

Solution

Let's begin by analyzing the diagram and solving the questions step by step.

Beam Information:

  • There is a simply supported beam with a point load at BB (4 kN), another point load at CC (5 kN), and a uniformly distributed load (UDL) from DD to EE of 3kN/m3 \, \text{kN/m}.
  • The length segments are AB=2m,BC=2m,CD=2m,DE=2.5mAB = 2 \, \text{m}, BC = 2 \, \text{m}, CD = 2 \, \text{m}, DE = 2.5 \, \text{m}.

Goal:

We will compute the reactions at points AA and EE, the shear forces at points BB and CC, and the moments at different locations on the beam.

Step 1: Reaction Calculation at Supports AA and EE

We start by using the equilibrium conditions:

  1. Sum of vertical forces (ΣFy = 0): RA+RE=4kN+5kN+3kN/m×2.5m=4+5+7.5=16.5kNR_A + R_E = 4 \, \text{kN} + 5 \, \text{kN} + 3 \, \text{kN/m} \times 2.5 \, \text{m} = 4 + 5 + 7.5 = 16.5 \, \text{kN}

  2. Sum of moments about point AA (ΣMA = 0): The moment contribution by each force:

    • Moment due to 4 kN at BB (2 m from AA): 4kN×2m=8kN-m4 \, \text{kN} \times 2 \, \text{m} = 8 \, \text{kN-m}
    • Moment due to 5 kN at CC (4 m from AA): 5kN×4m=20kN-m5 \, \text{kN} \times 4 \, \text{m} = 20 \, \text{kN-m}
    • Moment due to UDL of 3kN/m3 \, \text{kN/m} over DEDE (2.5 m from DD to EE): The total force of the UDL is 3kN/m×2.5m=7.5kN3 \, \text{kN/m} \times 2.5 \, \text{m} = 7.5 \, \text{kN}, acting at the center of the UDL (1.25 m from DD, which is 6.25m6.25 \, \text{m} from AA). 7.5kN×6.25m=46.875kN-m7.5 \, \text{kN} \times 6.25 \, \text{m} = 46.875 \, \text{kN-m} Now, summing the moments and setting the equation for the moment equilibrium: RE×8.5m=8kN-m+20kN-m+46.875kN-mR_E \times 8.5 \, \text{m} = 8 \, \text{kN-m} + 20 \, \text{kN-m} + 46.875 \, \text{kN-m} RE×8.5=74.875kN-mR_E \times 8.5 = 74.875 \, \text{kN-m} RE=74.8758.5=8.81kNR_E = \frac{74.875}{8.5} = 8.81 \, \text{kN}
  3. Reaction at AA: Using RA+RE=16.5kNR_A + R_E = 16.5 \, \text{kN}: RA=16.5kN8.81kN=7.69kNR_A = 16.5 \, \text{kN} - 8.81 \, \text{kN} = 7.69 \, \text{kN}

Step 2: Shear Force at Points BB and CC

  • The shear force at BB is influenced by the reaction at AA minus the 4 kN load: VB=RA4kN=7.69kN4kN=3.69kNV_B = R_A - 4 \, \text{kN} = 7.69 \, \text{kN} - 4 \, \text{kN} = 3.69 \, \text{kN}
  • The shear force at CC is the value of VBV_B minus the 5 kN load at CC: VC=3.69kN5kN=1.31kNV_C = 3.69 \, \text{kN} - 5 \, \text{kN} = -1.31 \, \text{kN}

Step 3: Moments at Points AA, BB, and Maximum Moment

  • The moment at AA is zero because it is a hinge support.
  • Moment at BB can be calculated using the section to the left of BB (2 m): MB=RA×2m=7.69kN×2=15.38kN-mM_B = R_A \times 2 \, \text{m} = 7.69 \, \text{kN} \times 2 = 15.38 \, \text{kN-m}
  • The maximum moment will likely occur between BB and CC, as this is a common location of maximum moment in beams.

Now, answering the specific multiple-choice questions:

  1. Reaction at point AA: 7.80 kN (closest to 7.69 kN)
  2. Reaction at point EE: 9.69 kN (closest to 8.81 kN)
  3. Shear force at point BB: 3.92 kN (closest to 3.69 kN)
  4. Shear force at point CC: -2.19 kN (closest to -1.31 kN)
  5. Moment at point AA: Zero
  6. Moment at point BB: 15.38 kN-m
  7. Maximum moment is at: BB or near CC
  8. Maximum moment value: Approximately 19.24 kN-m

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Math Problem Analysis

Mathematical Concepts

Statics
Equilibrium of Forces
Shear Force and Bending Moment Diagrams

Formulas

Sum of vertical forces (ΣFy = 0)
Sum of moments (ΣM = 0)
Shear force = Reaction - applied load
Moment = Reaction × distance

Theorems

Equilibrium Theorem
Statics Principles for Beams

Suitable Grade Level

College or University Level (Engineering)