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course Phy 201
10/4 10Questions about lab
`qx001. Most of you found that the period of motion for the balance when the large paperclip was suspended in water was less than that for the straightened small paperclip. What were the two periods, and what was the ratio of the two?
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The period of the small paperclip suspended in water is 13.2 s/5 periods=2.64 s/period. The period of the large paperclip suspended in water is 3.6 s/ 2 periods= 1.8 s/period. The ratio is 2.64:1.8 or 1.5:1.
Just a note, I had problems with my balance and these are the best results I derived after “fixing” it the best I could. I think they are relatively accurate and they do represent the logical expectation of what was to happen.
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`qx002. Which system experiences the greater change in buoyant force when the clip goes a centimeter deeper.
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The system with the larger paperclip experiences greater change in buoyant force when the clip goes a centimeter deeper because it has a larger mass than the smaller clip. Additionally, there is more of large paperclip in the water to begin with.
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`qx003. Give your best explanation why you would expect the system with the large suspended paperclip to have the shorter period.
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I would expect the large suspended paperclip to have a shorter period versus the single, straight small paperclip because the larger paperclip has more surface area to “drag” through the water, thus slowing it down more quickly than the smaller paperclip.
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`qx004. Speculate on whether the period of motion would remain constant through several cycles, if instead of a paperclip or wire the suspended object was a thin metal cone. What difference would it make if the cone was suspended from its apex as opposed to its base? What if instead of a cone the suspended object was a sphere? These are big open questions that can easily go beyond the scope of this course so don't spend an inordinate amount of time thinking about them, but do give the cone some thought. Hint: how would the buoyant force change with the depth to which the object is suspended in the water?
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If the metal cone was suspended, apex first it would have a lesser buoyant force than if it was suspended base first. The larger portion in the water would displace more water than the point of the apex. The period of motion would be lesser for the cone suspended base first versus suspended apex first. If the object was a sphere, it would not make a difference how it was suspended because it is perfected rounded; however, when compared to the metal cone suspended, it would have a lesser period of motion.
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Good responses. Your ratio of periods is about what I would expect, but I purposely haven't done the measurements to confirm.
Of course we'll be discussing this more in class.
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