The centre of mass of a non-uniform rod is not necessarily at the rod's mid-point. 4. A non-uniform beam AB of length 60 m and mass 5N rests on a pivot at the mid-point C. When a mass of 2N rests on the beam 15 m from B, the system is in equilibrium. Find the distance between A and the centre of mass of the beam. R

7. Find the distance a person can be from the wall and still be in equilibrium. Hanging mass-21 kg Mass of person 90 kg Distance to support = 6 m Distance to mass = 8m Distance to wall: ?? Mass of beam 15 kg (pivot point is the left side of beam & wall-no forces act there) Support

Answer should be : Mo : 189.3 lb ft, O = 18.5 lb at 248 from positive axes

Three identical 8.60-kg masses are hung by three identical springs, as shown in the figure. (Figure 1) Each spring has a force constant of 5.90 kN/m and was 11.0 cm long before any masses were attached to it. Make a free-body diagram for the top mass. Draw the vectors starting at the black dot at the center of the top mass.