List of top Applied Mechanics and Design Questions on Free-body diagrams and equilibrium

A rigid massless tetrahedron is placed such that vertex O is at the origin and the other three vertices A, B, and C lie on the coordinate axes as shown in the figure. The body is acted on by three point loads, of which one is acting at A along x-axis and another at point B along y-axis. For the body to be in equilibrium, the third point load acting at point O must be

The phases present in pearlite are

A rigid beam AD of length $3a = 6$ m is hinged at A and supported by two strings as shown. A force $F = 9$ kN is applied at C. Assuming small deflection and linear elastic strings, the tension in the string at C is __________ kN (round off to 2 decimal places).

A square plate is supported in four different ways (configurations (P) to (S) as shown in the figure). A couple moment $C$ is applied on the plate. Assume all the members to be rigid and mass-less, and all joints to be frictionless. All support links of the plate are identical. The square plate can remain in equilibrium in its initial state for which one or more of the following support configurations?