Q. The rectangular gate CD shown in the figure is 1.8m wide and 2.0 long. Assuming the material of the gate to be homogeneous and neglecting friction at the hinge C, determine the weight of the gate necessary to keep it shut until the water level rises to 2.0m above the hinge.
Q. Ricardo, of mass 74 kg, and Carmelita, who is lighter, are enjoying Lake Merced at dusk in a 33 kg canoe. When the canoe is at rest in the placid water, they exchange seats, which are 3.0 m apart and symmetrically located with respect to the canoe's center. Ricardo notices that the canoe moves 52.6 cm horizontally relative to a pier post during the exchange and calculates Carmelita's mass. What is it?