Kognity IB Physics A.0 Measurements & Uncertainty (id: d206553aa)

[单选题]
The time for two events, a gorlh3s9+ 9s-0m f:wzr*njg 8g ijd(dand b, are m/s790 dsx5v1ndl v(ox vcp lz+easured to be $(5.1 \pm 0.1)s$ and $(4.9 \pm 0.1)s$ respectively. In which of the following quantities is the fractional(percent) uncertainty the smallest?

A. $a+b$
B. $a-b$
C. $a \times b$
D. $a/b$


参考答案:  A


本题详细解析:
C and D will both have identical fractional uncertainties. * yu ss,2 lirrrlml:)bcp e/58They cannot both be the smallest, so they m p2 *bu/) 5lmr:,rsrycsl i8elust both be incorrect. A and B will have the same absolute uncertainty (0.2 s), but A is a large number (10) compared to B (0.2). Hence fractional uncertainty of A is the smallest.