Considering a plane truss having M-number of members, N-number of joints, and R-number of reactions at its supports. Which of the following equation indicates that the truss is statically determinate in nature?

Considering a plane truss having M-number of members, N-number of joints, and R-number of reactions at its supports. Which of the following equation indicates that the truss is statically determinate in nature? Correct Answer M + R = 2N

Explanation:

Truss: 

• A framework composed of members joined at their ends to form a rigid structure.
• Stability can often be determined by examining the adequacy of external supports and internal member connections. If M + R < 2N, however, then it is always unstable, because there is not enough number of members or supports to provide adequate constraints to prevent a truss from turning into a mechanism under certain loads.
• For a stable plane truss, if M + R = 2N, then it is statically determinate.
• A simple truss is stable and determinate.
• For a stable plane truss, if M + R > 2N, then it is statically indeterminate. The discrepancy between the two numbers, M + R - 2N, is called the degrees of indeterminacy, or the number of redundant forces.