As the reservoir behind a dam is filled with water, the pressure that the water exerts on the dam increases. Eventually, the force on the dam becomes substantial, and it could cause the dam to collapse. There are two significant issues to be considered: First, the base of the dam should be able to withstand the pressure rho gh, where rho is the density of the water behind the dam, h is its depth, and g is the magnitude of the acceleration due to gravity. This means that the material of which the dam is made needs to be strong enough so that it doesn’t crack (compressive strength).The second issue has to do with the strength of the foundation of the dam. The water pressure exerts a clockwise torque on the dam, as shown in the figure. The foundation of the dam should be strong enough so that the dam does not topple. The material has to be strong enough that the dam does not snap (shear strength).To study this phenomenon, consider the simple model of a dam depicted in the diagram.  View Figure  A reservoir of water (density rho) behind the dam is filled to a height h. Assume that the width of the dam (the dimension pointing into the screen) is La). Consider a horizontal layer of the dam wall of thickness dx located a distance x above the reservoir floor. What is the magnitude dF of the force on this layer due to the water in the reservoir? (in terms of x, dx, or other terms in the problem) b) The force of the water produces a torque on the dam. In a simple model, if the torque due to the water were enough to cause the dam to break free from its foundation, the dam would pivot about its base (point P). What is the magnitude tau of the torque about the point P due to the water in the reservoir?Express your answer in terms of quantities given in the problem introduction and the magnitude of the acceleration due to gravity g.

Compose a 250 words essay on Fossils (Earth Science Class). Needs to be plagiarism free!

They are an important resource for identifying the types of species living during a particular era. Body fossils are the actual parts of the organisms and are rare to find as they can only be found in the places where the organisms actually lived. They provide very important information regarding the physical appearance of the organism but they are still ignorant to their lifestyle. Trace fossils include footprints, pathways and droppings. These offer an insight into the lifestyle of these organisms.

The time durations in the study of fossils and rocks are huge. hence a geological time scale has been developed. The major subdivisions of the geological time scale are eons, eras, periods and epochs with eon indicating a span of hundreds of millions of years. Comparison between the features of different sedimentary rocks and the type of fossils present in it can be used to establish age relationships between different strata of Earth’s crust. This is known as correlation and is an important tool in the study of fossils and rocks (Lutgens, Tarbuck, &