# HW1-2012 - gravity? 3. (4 points) The ﬁrst measurements...

HW1-2012
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ECH 152A, Fall 2011, Roland Faller Homework 1, October 1, 2012 Due: October 8, Beginning of Lecture 1. (4 points) UNITS Electric current is the fundamental SI dimension with unit Ampere . For the following quantities combine fundamental SI units to obtain derived SI units Electric power, electric charge, resistance, and voltage. 2. (4 points) A mercury manometer at 25 C gives a reading of 72.78 cm at a point where the local acceleration of gravity is 9.81 ms - 2 . The atmo- spheric pressure is 100.78 kPa. What is the absolute pressure being measured? ρ Hg (25 C) = 13 . 534gcm - 3 . How does it change with the local acceleration of
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Unformatted text preview: gravity? 3. (4 points) The ﬁrst measurements of the properties of high–pressure gases (e.g. carbon dioxide) were made by Amagat in France in the 1860s and 1870s. He worked in a mine shaft using a mercury manometer in a glass instrument for pressures up to 400 bar (approx 40 MPa). (He actually later improved his design to go to 3200 bar using a hydraulic design.) Estimate the size of the instrument needed (for 400 bar). If you assume the diameter of the mercury column was 1 cm, what was the weight of the mercury in the instrument?...
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