1 Buoyancy (also known as the buoyant force) is the force exerted on an object that is wholly or partly immersed in a fluid. 2  The symbol for the magnitude of buoyancy is B or FB.3  As a vector it must be stated with both magnitude and direction. Buoyancy (also known as the buoyant force) is the force exerted on an object that is wholly or partly immersed in a fluid. 2  The symbol for the magnitude of buoyancy is B or FB.
epicenter. 1  Also, epicentrum. Geology. a point, directly above the true center of disturbance, from which the shock waves of an earthquake apparently radiate. 2  a focal point, as of activity: Manhattan's Chinatown is the epicenter of the city's Chinese community.
Hypocenter. the focal point of an earthquake. The depth at which a hypocenter lies can vary from 0 to 700 km. The source of underground shock is movements along tectonic faults, which vary in length up to hundreds of kilometers. In this sense, the hypocenter means the point from which the fault began to rip open.