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        本题目来源于试卷:  Kognity IB Physics A.0 Measurements & Uncertainty ,类别为 IBDP Physics 本题为动态变量类型,下面题目描述与解答中出现的数值不同于您在作答时遇到的数值! 
[单选题]A piece of string 9.5 ± a.m4hej/2f8  +9 9 mqpylobuuh3jp e5q0.2 cxgdp:3qi znft5;5zf   d7p,.xqm long is cut from a longer piece that is 12.6 ± 0.2 cm long. How long is the remaining piece on 5  idpf7;,g5q.pd tzqxf:xz3f string?
 
 
 
A. $3.1 \pm 0.2 \; cm$ B. $3.1 \pm 0.3 \; cm$
 C. $3.1 \pm 0.4 \; cm$
 D. $3.1 \pm 0.5 \; cm$
 
 
 参考答案:  C
 
 
 本题详细解析:
 $y=a-b=12.6-9.5=3.1 \mathrm{~cm}$ $\Delta y=\Delta a+\Delta b=0.2+0.2=0.4 \mathrm{~cm}$
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