15. Determine if a truss with 8 joints and 15 members is stable. Explain why or why not. __

## Step 1<br />The stability of a truss is determined by the number of joints and members it has. According to the principle of static equilibrium, a truss is stable if it has at least one degree of freedom less than the number of members. This means that the number of joints should be at least one less than the number of members.<br /><br />## Step 2<br />In this case, the truss has 8 joints and 15 members. If we subtract the number of joints number of members, we get \(15 - 8 = 7\). This means that the truss has 7 degrees of freedom, which is more than the number of members.<br /><br />## Step 3<br />This indicates that the truss is not stable because it has more degrees of freedom than the number of members. This means that the truss can move or rotate in more directions than the number of members can constrain it.