Consider a tripod placed on a floor; its leg is connected using a ball and socket joint at A and the other end B is on the floor. When the resultant force and the resultant couple moment acting on the leg is zero, the leg is said to be in equilibrium and can be expressed with the help of equations of equilibrium. Since the leg is under equilibrium, it satisfies the vector and scalar equations of equilibrium. According to the vector equations of equilibrium, all external forces acting on the leg must have a vector sum of zero. The vector sum of all couple moments and the moments of all the forces about a point must also be equal to zero. According to the scalar equations of equilibrium, if the external forces are expressed in the cartesian form, then the summation of the component of forces along the respective directions must be zero. Similarly, the scalar summation of the components of a moment in the x, y, and z axes must also be zero.