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MasteringPhysics: Assignment Print View http://session.masteringphysics.com/myct/assignmentPrint?assignm... 1 of 13 10/11/08 11:45 PM [ Print View ] Physics 2211-001, Fall 2008 Energy Due at 11:00pm on Monday, September 29, 2008 View Grading Details Problem 10.25 A 48.0 marble moving at 2.30 strikes a 30.0 marble at rest. What is the speed of each marble immediately after the collision? Part A ANSWER: = 0.531 m/s Part B ANSWER: = 2.83 m/s Hooke's Law Learning Goal: To understand the use of Hooke's law for a spring. Hooke's law states that the restoring force on a spring when it has been stretched or compressed is proportional to the displacement of the spring from its equilibrium position. The equilibrium position is the position at which the spring is neither stretched nor compressed. Recall that means that is equal to a constant times . For a spring, the proportionality constant is called the spring constant and denoted by . The spring constant is a property of the spring and must be measured experimentally. The larger the value of , the stiffer the spring. In equation form, Hooke's law can be written . The minus sign indicates that the force is in the opposite direction to that of the spring's displacement from its equilibrium length and is "trying" to restore the spring to its equilibrium position. The magnitude of the force is given by , where is the magnitude of the displacement. In Haiti, public transportation is often by taptaps, small pickup trucks with seats along the sides of the pickup bed and railings to which passengers can hang on. Typically they carry two dozen or more passengers plus an assortment [ Print ] MasteringPhysics: Assignment Print View http://session.masteringphysics.com/myct/assignmentPrint?assignm... 2 of 13 10/11/08 11:45 PM of chickens, goats, luggage, etc. Putting this much into the back of a pickup truck puts quite a large load on the truck springs. A truck has springs for each wheel, but for simplicity assume that the individual springs can be treated as one spring with a spring constant that includes the effect of all the springs. Also for simplicity, assume that all four springs compress equally when weight is added to the truck and that the equilibrium length of the springs is the length they have when they support the load of an empty truck. Part A A 60- driver gets into an empty taptap to start the day's work. The springs compress 0.02 . What is the effective spring constant of the spring system in the taptap? Hint A.1 How to approach the problem Hint not displayed Enter the spring constant numerically in newtons per meter. ANSWER: = 2.94 1 0 4 Part B After driving a portion of the route, the taptap is fully loaded with a total of 25 people with an average mass of 60 per person. In addition, there are three 15- goats, five 3- chickens, and a total of 25 of bananas on their way to the market. Assume that the springs have somehow not yet compressed to their maximum amount. How much are the springs compressed?much are the springs compressed?... View Full Document

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