A simply supported beam is loaded as shown in FIGURE 1. By referring to FIGURE 1 determine the following: The reaction forces at supports B and D. Draw the shear force diagram for the beam. Calculate the coordinates of the centroid of the lamina shown in FIGURE 2.

Question

Asked on August 1, 2026Physics

This physics problem tests your understanding of fundamental physical laws and their applications. The step-by-step solution below breaks down the problem using relevant equations and physical reasoning.

Accepted Answer · 2026-08-01T19:32:13.425Z

Here are the solutions to Question 5: Question 5.1: Simply Supported Beam Step 1: Identify all forces and their positions. Let the origin be at point A. Point load at A: F_A = 18 kN (downwards) at x = 0 m. Uniformly Distributed Load (UDL): w = 6 kN/m from x = 0 m to x = 5 m (total length 5 m). The equivalent point load for the UDL is F_UDL = 6 kN/m × 5 m = 30 kN, acting at the centroid of the UDL, which is x = 5/2 = 2.5 m. Support at B: Reaction R_B (upwards) at x = 1.5 m. Point load: F_40 = 40 kN (downwards) at x = 1.5 m + 3.5 m = 5 m. Support at D: Reaction R_D (upwards) at x = 5 m + 1.5 m = 6.5 m. Point load at E: F_E = 22 kN (downwards) at x = 6.5 m + 2.5 m = 9 m. 5.1.1 Determine the reaction forces at supports B and D. Step 2: Apply equilibrium equations. Sum of moments about B ( M_B = 0). Assume clockwise moments are positive. The distances are measured from B (x=1.5 m). F_A: 18 kN at x=0. Moment arm = 1.5 m. Moment = 18 × 1.5 (clockwise). F_UDL: 30 kN at x=2.5 m. Moment arm = 2.5 - 1.5 = 1 m. Moment = 30 × 1 (clockwise). F_40: 40 kN at x=5 m. Moment arm = 5 - 1.5 = 3.5 m. Moment = 40 × 3.5 (clockwise). R_D: R_D at x=6.5 m. Moment arm = 6.5 - 1.5 = 5 m. Moment = R_D × 5 (counter-clockwise). F_E: 22 kN at x=9 m. Moment arm = 9 - 1.5 = 7.5 m. Moment = 22 × 7.5 (clockwise). M_B = (18 × 1.5) + (30 × 1) + (40 × 3.5) - (R_D × 5) + (22 × 7.5) = 0 27 + 30 + 140 - 5R_D + 165 = 0 362 - 5R_D = 0 5R_D = 362 R_D = (362)/(5) = 72.4 kN Sum of vertical forces ( F_y = 0). Assume upwards forces are positive. R_B + R_D - F_A - F_UDL - F_40 - F_E = 0 R_B + 72.4 kN - 18 kN - 30 kN - 40 kN - 22 kN = 0 R_B + 72.4 kN - 110 kN = 0 R_B - 37.6 kN = 0 R_B = 37.6 kN The reaction forces are: R_B = 37.6 kN R_D = 72.4 kN 5.1.2 Draw the shear force diagram for the beam. Step 3: Calculate shear force values at key points. At A (x=0): V_A = -18 kN (due to downward point load) Just before B (x=1.5^-): V_B^- = -18 kN - (6 kN/m × 1.5 m) = -18 - 9 = -27 kN Just after B (x=1.5^+): V_B^+ = V_B^- + R_B = -27 kN + 37.6 kN = 10.6 kN Just before 40 kN load (x=5^-): The UDL continues from B to x=5 m. Length from B to x=5 m is 5 - 1.5 = 3.5 m. V_40^- = V_B^+ - (6 kN/m × 3.5 m) = 10.6 - 21 = -10.4 kN Just after 40 kN load (x=5^+): V_40^+ = V_40^- - 40 kN = -10.4 - 40 = -50.4 kN Just before D (x=6.5^-): No UDL between x=5 m and x=6.5 m. V_D^- = -50.4 kN Just after D (x=6.5^+): V_D^+ = V_D^- + R_D = -50.4 kN + 72.4 kN = 22 kN Just before E (x=9^-): No loads between D and E. V_E^- = 22 kN At E (x=9): V_E = V_E^- - 22 kN = 22 - 22 = 0 kN Step 4: Sketch the shear force diagram. The shear force diagram will show: A linear decrease from -18 kN at A to -27 kN at B. A sudden jump up by 37.6 kN at B, from -27 kN to 10.6 kN. A linear decrease from 10.6 kN at B to -10.4 kN at x=5 m (where the 40 kN load is applied). A sudden jump down by 40 kN at x=5 m, from -10.4 kN to -50.4 kN. A constant value of -50.4 kN from x=5 m to D. A sudden jump up by 72.4 kN at D, from -50.4 kN to 22 kN. A constant value of 22 kN from D to E. A sudden jump down by 22 kN at E, from 22 kN to 0 kN. ` Shear Force Diagram (SFD) (Values in kN) | 10.6| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ✂️ _That answer was long and got cut off. Reply continue and I'll finish it._

Accepted Answer · 2026-08-01T19:32:13.425Z

Here are the solutions to Question 5: Question 5.1: Simply Supported Beam Step 1: Identify all forces and their positions. Let the origin be at point A. Point load at A: F_A = 18 kN (downwards) at x = 0 m. Uniformly Distributed Load (UDL): w = 6 kN/m from x = 0 m to x = 5 m (total length 5 m). The equivalent point load for the UDL is F_UDL = 6 kN/m × 5 m = 30 kN, acting at the centroid of the UDL, which is x = 5/2 = 2.5 m. Support at B: Reaction R_B (upwards) at x = 1.5 m. Point load: F_40 = 40 kN (downwards) at x = 1.5 m + 3.5 m = 5 m. Support at D: Reaction R_D (upwards) at x = 5 m + 1.5 m = 6.5 m. Point load at E: F_E = 22 kN (downwards) at x = 6.5 m + 2.5 m = 9 m. 5.1.1 Determine the reaction forces at supports B and D. Step 2: Apply equilibrium equations. Sum of moments about B ( M_B = 0). Assume clockwise moments are positive. The distances are measured from B (x=1.5 m). F_A: 18 kN at x=0. Moment arm = 1.5 m. Moment = 18 × 1.5 (clockwise). F_UDL: 30 kN at x=2.5 m. Moment arm = 2.5 - 1.5 = 1 m. Moment = 30 × 1 (clockwise). F_40: 40 kN at x=5 m. Moment arm = 5 - 1.5 = 3.5 m. Moment = 40 × 3.5 (clockwise). R_D: R_D at x=6.5 m. Moment arm = 6.5 - 1.5 = 5 m. Moment = R_D × 5 (counter-clockwise). F_E: 22 kN at x=9 m. Moment arm = 9 - 1.5 = 7.5 m. Moment = 22 × 7.5 (clockwise). M_B = (18 × 1.5) + (30 × 1) + (40 × 3.5) - (R_D × 5) + (22 × 7.5) = 0 27 + 30 + 140 - 5R_D + 165 = 0 362 - 5R_D = 0 5R_D = 362 R_D = (362)/(5) = 72.4 kN Sum of vertical forces ( F_y = 0). Assume upwards forces are positive. R_B + R_D - F_A - F_UDL - F_40 - F_E = 0 R_B + 72.4 kN - 18 kN - 30 kN - 40 kN - 22 kN = 0 R_B + 72.4 kN - 110 kN = 0 R_B - 37.6 kN = 0 R_B = 37.6 kN The reaction forces are: R_B = 37.6 kN R_D = 72.4 kN 5.1.2 Draw the shear force diagram for the beam. Step 3: Calculate shear force values at key points. At A (x=0): V_A = -18 kN (due to downward point load) Just before B (x=1.5^-): V_B^- = -18 kN - (6 kN/m × 1.5 m) = -18 - 9 = -27 kN Just after B (x=1.5^+): V_B^+ = V_B^- + R_B = -27 kN + 37.6 kN = 10.6 kN Just before 40 kN load (x=5^-): The UDL continues from B to x=5 m. Length from B to x=5 m is 5 - 1.5 = 3.5 m. V_40^- = V_B^+ - (6 kN/m × 3.5 m) = 10.6 - 21 = -10.4 kN Just after 40 kN load (x=5^+): V_40^+ = V_40^- - 40 kN = -10.4 - 40 = -50.4 kN Just before D (x=6.5^-): No UDL between x=5 m and x=6.5 m. V_D^- = -50.4 kN Just after D (x=6.5^+): V_D^+ = V_D^- + R_D = -50.4 kN + 72.4 kN = 22 kN Just before E (x=9^-): No loads between D and E. V_E^- = 22 kN At E (x=9): V_E = V_E^- - 22 kN = 22 - 22 = 0 kN Step 4: Sketch the shear force diagram. The shear force diagram will show: A linear decrease from -18 kN at A to -27 kN at B. A sudden jump up by 37.6 kN at B, from -27 kN to 10.6 kN. A linear decrease from 10.6 kN at B to -10.4 kN at x=5 m (where the 40 kN load is applied). A sudden jump down by 40 kN at x=5 m, from -10.4 kN to -50.4 kN. A constant value of -50.4 kN from x=5 m to D. A sudden jump up by 72.4 kN at D, from -50.4 kN to 22 kN. A constant value of 22 kN from D to E. A sudden jump down by 22 kN at E, from 22 kN to 0 kN. ` Shear Force Diagram (SFD) (Values in kN) | 10.6| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ✂️ _That answer was long and got cut off. Reply continue and I'll finish it._

A simply supported beam is loaded as shown in FIGURE 1. By referring to FIGURE 1 determine the following: The reaction forces at supports B and D. Draw the shear force diagram for the beam. Calculate the coordinates of the centroid of the lamina shown in FIGURE 2.

Question 5.1: Simply Supported Beam

Need help with your own homework?

More Physics Questions

A simply supported beam is loaded as shown in FIGURE 1. By referring to FIGURE 1 determine the following: The reaction forces at supports B and D. Draw the shear force diagram for the beam. Calculate the coordinates of the centroid of the lamina shown in FIGURE 2.

Question 5.1: Simply Supported Beam

Need help with your own homework?

More Physics Questions