Shear flow themselves. In a shearing flow, adjacent layers of fluid move parallel to each other with different speeds. Viscous fluids resist this shearing motion. For a Newtonian fluid, the stress exerted by the fluid in resistance to the shear is proportional to the strain rate or shear rate. A simple example of a shear flow is Couette flow, in which a fluid is trapped between two large parallel plates, and one plate is moved with some relative velocity to the other. Here, the strain rate is simply the relative velocity divided by the distance between the plates. Shear flows in fluids
Brief Answers to the Big Questions at your feet ... Try to make sense of what you see, and wonder about what makes the universe exist ... It matters that you don't give up. Unleash your imagination. Shape the future." Physicist Marcelo Gleiser, reviewing the book for NPR, writes: "Stephen Hawking is one of those rare luminaries whose life symbolizes the best humanity has to offer ... [his book is one] every thinking person worried about humanity's future should read ... If there is a unifying theme across the book, it is Hawking's deep faith in science's ability to solve humanity's biggest problems ... His answers