The porcupine is very different from other rodents in North America because it is so large, has a big head and, of course, because of its long quills. Porcupines have around 30,000 quills, mostly on their backs and rumps. The longest quills are near the tail and the shortest are on their cheeks.
The divergence of a vector field simply measures how much the flow is expanding at a given point. It does not indicate in which direction the expansion is occuring. Hence (in contrast to the curl of a vector field), the divergence is a scalar.he fact that fluid is flowing out of the sphere is a sign of the positive divergence of the vector field. Rotate with mouse to change perspective. You can move the sphere by dragging it with the mouse.
Distance is the scalar measurement of a length or interval between two points and is measured by considering the complete path that it takes to get from one point to another. Displacement is the vector measure of an interval between two locations and describes the shortest path connecting them. The actual or scalar measure is what is described as the scientific definition of distance. For example, consider an example in which a man walks from his house to his car and back.