Ch 1 Physics for Scientists and Engineers

# Ch 1 Physics for Scientists and Engineers - 1.1 Solve 1.2...

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1.1. Solve:

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1.2. Solve:
1.3. Solve: (a) The basic idea of the particle model is that we will treat an object as if all its mass is concentrated into a single point. The size and shape of the object will not be considered. This is a reasonable approximation of reality if: i) the distance traveled by the object is large in comparison to the size of the object, and ii) rotations and internal motions are not significant features of the object’s motion. The particle model is important in that it allows us to simplify a problem. Complete reality—which would have to include the motion of every single atom in the object—is too complicated to analyze. By treating an object as a particle, we can focus on the most important aspects of its motion while neglecting minor and unobservable details. (b) The particle model is valid for understanding the motion of a satellite or a car traveling a large distance. (c) The particle model is not valid for understanding how a car engine operates, how a person walks, how a bird flies, or how water flows through a pipe.

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1.4. Solve: Position refers to the location of an object at a given time relative to a coordinate system. Dis- placement, on the other hand, is the difference between the object’s final position at time t 1 and the initial position at time t 0 . Displacement is a vector, whose direction is from the initial position toward the final position. An airplane at rest relative to a runway lamp, serving as the origin of our coordinate system, will have a position, called the initial position. The location of the airplane as it takes off may be labeled as the final position. The difference between the two positions, final minus initial, is displacement.
1.5. Solve: (a) An operational definition defines a concept or an idea in terms of a procedure , or a set of operations, that is used to identify or measure the concept. (b) The displacement r r of an object is a vector found by drawing an arrow from the object’s initial location to its final location. Mathematically, rrr =− fi . The average velocity r v of an object is a vector that points in the same direction as the displacement r r and has length, or magnitude, ∆∆ r rt /, where tt t is the time interval during which the object moves from its initial location to its final location.

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1.6. Solve: The player starts from rest and moves faster and faster (accelerates).
1.7. Solve: The particle starts with an initial velocity but as it slides it moves slower and slower till coming to rest. This is a case of negative acceleration because it is an acceleration opposite to the positive direction of motion.

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1.8. Solve: The acceleration of an object is a vector formed by finding the ratio of r v , the change in the object’s velocity, to t , the time in which the change occurs. The acceleration vector r a points in the direction of r v , which is found by vector subtraction.
1.9.

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## This homework help was uploaded on 04/07/2008 for the course PHSX 211/212 taught by Professor Medvedev during the Spring '08 term at Kansas.

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Ch 1 Physics for Scientists and Engineers - 1.1 Solve 1.2...

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