Can You Pass This Physics Quiz On Force? Part II

The correct answer is "all" because the forces in the members of simple trusses can be analyzed using any of the mentioned methods. The method of joints involves analyzing the forces at each joint of the truss, while the method of sections involves cutting the truss into sections and analyzing the forces in those sections. The graphical method involves constructing a graphical representation of the truss and analyzing the forces using graphical techniques. Therefore, all of these methods can be used to analyze the forces in the members of simple trusses.

The statement "all" is the correct answer because all of the statements provided are true. The ratio of plastic moment to the yield moment is indeed called the shape factor. The moment at which the entire section of the beam becomes fully plastic is referred to as the plastic moment. In the fully plastic stage of the beam, the neutral axis does divide the section into two sections of equal area. Therefore, all of the statements are correct.

The maximum sagging moment occurs at a distance of .211L from the ends of the symmetrical three hinged parabolic arch.

In a rigid jointed plane frame, each member can have a maximum of three unknown internal forces. This is because a member can experience forces in three different directions: tension, compression, or no force at all. Therefore, the correct answer is 3.

The carryover factor in a prismatic member whose far end is fixed is 1/2. This means that only half of the axial force or moment at the far end of the member is transferred to the adjacent member or support. The other half is assumed to be carried over to the next member or support. This factor is used in structural analysis to accurately determine the distribution of forces and moments in a prismatic member with fixed ends.

The deflection at any point of a perfect frame can be obtained by applying a unit load at the joint in the direction in which the deflection is required. This means that in order to determine the deflection at a specific point, a unit load needs to be applied in the same direction as the desired deflection.

The point of contraflexure is the point where the bending moment (B.M.) changes sign. This means that the bending moment shifts from positive to negative or vice versa. At this point, the bending moment is neither minimum nor maximum, but rather undergoes a change in direction. This can occur in beams or other structural elements when there is a transition from compression to tension or vice versa.

When a uniformly distributed load moves from left to right along a girder, the conditions for maximum bending moments at a section are that the load position should be such that the section divides the load in the same ratio as it divides the span. This means that the load should be positioned in a way that the portion of the load on one side of the section is proportional to the length of the span on that side. This ensures that the bending moment is maximized at the section.

In a rigid jointed plane frame, the stability and static determinacy are determined by the number of unknowns (m and r) and the number of equations (j) available. The equation (3m+r) = 3j suggests that the number of unknowns (m and r) is equal to three times the number of equations (j). This indicates that there is a unique solution for the unknowns, making the frame stable and statically determinate.

In the displacement method of structural analysis, the basic unknowns refer to the variables that need to be determined in order to solve the problem. In this method, the unknowns are the displacements of the various points or elements in the structure. By solving the equations based on the equilibrium and compatibility conditions, the displacements can be calculated, allowing for the determination of the overall behavior and response of the structure. Therefore, the correct answer is "Displacements".

The correct answer is "Column analogy method." The column analogy method is a force method of structural analysis. It involves representing the structure as an equivalent column, where the loads and reactions are replaced by forces and moments. The method is based on the assumption that the structure behaves like a series of interconnected columns, and the analysis involves determining the internal forces and displacements in each column. This method is commonly used for analyzing indeterminate structures and is a powerful tool in structural engineering.

The statement "product of moment of inertia is zero" is correct because the product of moment of inertia is zero when the section is symmetric about both axes. This means that the section has equal moments of inertia about both axes and the product of these two moments is zero.

The shape factor for a triangular section in plastic analysis is 2.34. This factor is used to determine the plastic moment capacity of the section, which is the maximum moment that the section can resist before it starts to yield and deform plastically. The shape factor takes into account the geometry of the triangular section, such as the length of its sides and the angles between them, to calculate its plastic moment capacity. In this case, the triangular section has a shape factor of 2.34, indicating its ability to resist bending moments.

Castigliano's second theorem is a method used to calculate deflections in structures. Unlike the first theorem, which is applicable only to statically determinate structures, the second theorem can be used for any type of structure. This theorem allows engineers to determine the deflection at a specific point under a load, regardless of the complexity or type of structure. It is a powerful tool that provides a more comprehensive understanding of the behavior of structures and aids in designing and analyzing various types of structures.

When one of the supports of a two hinge arch settles down vertically, it causes a change in the distribution of forces within the arch. This settling down results in a decrease in the horizontal thrust exerted by the arch. As the support settles, it reduces the resistance offered by that support to the horizontal forces acting on the arch, leading to a decrease in the overall horizontal thrust. Therefore, the correct answer is that the horizontal thrust is decreased.