And velocity the rate change displacement with time
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F
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Mass
| F | � |
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where c is a constant.
3. Mass
| F | � |
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Displacement y
| (a) | Applied | Mass | Force | Mass |
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| (b) | |||||
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| mass becoming involved, the | |||||
| forces and displacement are | |||||
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| horizontal. The rollers enable | |||||
Solution
To obtain the system model we draw free-body diagrams, these being diagrams of masses showing just the external forces acting on each mass. For the system in Figure 18.84(a) we have just one mass and so just one free-body diagram and that is shown in Figure 18.84(b) . As the free-body diagram indicates, the net force acting on the mass is the applied force minus the forces exerted by the spring and by the dashpot:
| net force � F | � | ky | � |
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| m d y dt 2� | F | � | ky | � |
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