For the highest accuracy, would you choose an aluminum or a steel tape rule for year-round outdoor use?
a. steel tape rule
b. either of the two
c. aluminum tape rule
Why?
I am not quite sure what this question is asking.
I took an educated guess of steel because all the number are less based on the following information. The less something expans the more accurate its graduations for its reading will be.
Steel Aluminum
thermal cond. 14J/(s.m.C) 240J/(s.m.C)
specific heat 452 900
coeff therm.exp .000023 .000012
I agree. The question is asking what material will be least affected by outdoor temperature variations
I am reminded of a lab I had all my Physics classes do: To try to determine the linear expansion of a concrete sidewalk (no expansion joints were in it, non-professionals laid it), it was about 300 feet long. I had the students measure it with a steel rule in August, when the temp was near 100F, and measure it again in Jan, when the temp was near 30F with the same steel rule. So the question is, what was the change in the rule, and in the concrete. You may want just do the rule changes for an exercise,,,,it is enlighting as to what just is a measurement, and what does it mean?
I think this answer was wrong although I didn't see the correct answer. The question is asking for the material leasr affected,thus, based on the coefficients of linear expansion, we can say that aluminium is more prone to expanding more compared to steel. The coefficient of linear expansion for steel is 12x10^-6 ,hich less than 23 x10^-6 for steel.
Therefore, steel tape rule would be the best choice for highest accuracy.
For the highest accuracy and least impact from outdoor temperature variations, the correct answer would be the steel tape rule. Steel has a lower coefficient of thermal expansion compared to aluminum, meaning it will expand and contract less with temperature changes. This stability helps maintain the accuracy of the graduations on the tape rule. On the other hand, aluminum has a higher coefficient of thermal expansion, making it more prone to expanding and contracting with temperature changes, which could lead to less accurate measurements.
To answer this question, we need to consider the coefficient of thermal expansion for both aluminum and steel. The coefficient of thermal expansion measures how much a material expands with a change in temperature.
The choices given are steel and aluminum. The coefficient of thermal expansion for steel is 12 x 10^-6 per degree Celsius, while the coefficient for aluminum is 23 x 10^-6 per degree Celsius.
Based on this information, we can see that aluminum has a higher coefficient of thermal expansion compared to steel. This means that aluminum will expand more with a change in temperature compared to steel.
For year-round outdoor use, where temperature variations are common, it would be ideal to choose a material that is least affected by these temperature changes. In this case, steel would be a better choice because it has a lower coefficient of thermal expansion, indicating that it will expand and contract less with changes in temperature compared to aluminum.
Therefore, the correct answer would be:
Answer: c. aluminum tape rule