MIBT Prac 3
Beams, force diagrams, internal forces, Shear force variations with loading conditions.
Shear force variation with increasing load
Measurements:
1- Set the digital display meter to zero with no load.
2- Apply a point load of 100 g between two supports at 10 cm from left support and record the shear force from the digital force display in the Table 1.
3- Please note that the positive sign on the digital display illustrates that the applied shear force to the right part of the bar at the cut section is downward. Therefore, the negative sign means that the shear force is upward.
4- Increase the load by 100 g intervals up to 400 g and repeat the step 2.
Calculations:
5- Draw the free body diagram of the system.
6- Calculate the theoretical shear force at the cut and complete Table 1.
7- Describe the structure performance and error sources.
8- Sketch the shear force versus applied load for both experimental and theoretical results, using MS-Excel or Origin. Do not sketch them manually.
Table 1- Effect of loading on Shear force
Mass (g) Load (N) Experimental shear force (N) Theoretical shear force (N)
100
200
300
400
Shear force variation for various loading conditions
Measurements:
1- Set the digital display meter to zero with no load.
2- Apply a point load of 200 g at 14 cm from left support as shown in Figure 1.
3- Record the shear force from the digital force display in the Table 2.

Figure 1- Configuration 1 for shear force
4- Apply two point loads of 100 g and 200 g at 22 cm and 26 cm from left support, respectively, as shown in Figure 2.
5- Record the shear force from the digital force display in the Table 2.

Figure 2- Configuration 2 for shear force
6- Apply two point loads of 100 g and 200 g at 24 cm and 40 cm from left support, respectively, as shown in Figure 3.
7- Record the shear force from the digital force display in the table 2.

Figure 3- Configuration 3 for shear force
Calculations:
9- Draw the free body diagram for each configuration.
10- Calculate the support reactions (F1 & F2)
11- Calculate the theoretical shear force at the cut for each configuration and complete Table 2.
Table 2- Effect of location of the load on Shear force
Configuration W1 (N) W2 (N) F1 (N) F2 (N) Experimental shear force (N) Theoretical shear force (N)
1
2
3
PRAC RELATED QUESTIONS:
1) if P1 = 9kN and P2 = 13 kN, find the shear force at C. Show your work by drawing a shear diagram and also by cutting a section at C.

2) Determine the shear force at C if P1=P2= 20 kN. Show your work by drawing a shear diagram and also by cutting a section at C.