Densities of some common substances at standard | Fig. , Figure A simple device for measuring the pressure exerted by a fluid. Table , Fig. , Figure A parcel of fluid (darker region) in a larger volume of fluid is singled out. The net force exerted on the parcel of fluid must be zero because it is in equilibrium. Fig. , Figure The external forces acting on the cube of liquid are the gravitational force Fg and the buoyant force B. Under equilibrium conditions, B = Fg. Fig. , Active Figure (a) A totally submerged object that is less dense than the fluid in which it is submerged experiences a net upward force. (b) A totally submerged object that is denser than the fluid sinks. At the Active Figures link at , you can move the object to new positions as well as change the density of the object to see the results. Fig. , Active Figure An object floating on the surface of a fluid experiences two forces, the gravitational force Fg and | Fig. , Figure A simple device for measuring the pressure exerted by a fluid. Table , Fig. , Figure A parcel of fluid (darker region) in a larger volume of fluid is singled out. The net force exerted on the parcel of fluid must be zero because it is in equilibrium. Fig. , Figure The external forces acting on the cube of liquid are the gravitational force Fg and the buoyant force B. Under equilibrium conditions, B = Fg. Fig. , Active Figure (a) A totally submerged object that is less dense than the fluid in which it is submerged experiences a net upward force. (b) A totally submerged object that is denser than the fluid sinks. At the Active Figures link at , you can move the object to new positions as well as change the density of the object to see the results. Fig. , Active Figure An object floating on the surface of a fluid experiences two forces, the gravitational force Fg and the buoyant force B. Because the object floats in equilibrium, B = Fg. At the Animated Figures link at , you can change the densities of the object and the fluid. Fig. , Figure An ice cube floats on the surface of water. What happens to the water level as the ice cube melts? Fig. , Figure (b) A ship can be damaged even when it is not near the visible ice. Fig. , Figure At any point on the surface of a submerged object, the force exerted by the fluid is perpendicular to the surface of the object. The force exerted by the fluid on the walls of the container is perpendicular to the walls at all points. Fig. , Figure (a) Diagram of a hydraulic press. Because the increase in pressure is the same on the two sides, a small force Fl at the left produces a much greater force F2 at the right. (b) A vehicle undergoing repair is supported by a hydraulic lift in a garage. (David Frazier) Fig. , Fig.