द्रवचालित प्रवणता रेखा (Hydraulic gradient line - HGL) प्रवाह की दिशा में किस शीर्ष (head) के परिवर्तन को दर्शाती है?

The ratio of the specific weight of a liquid to the specific weight of a standard fluid is known as:

The magnitude of the buoyant force depends on the _____________.

In incompressible fluid dynamics, the continuity equation is ∂u/∂x + ∂v/∂y + ∂w/∂z = 0. What physical law does this equation represent?