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

[单选题]
The time for two events, a and b+ o 4*rlv,mpsi-jtrwzef 7;w2 , are measured to b:y(/pye oxv4fe $(5.1 \pm 0.1)s$ 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 u j/qhv99qneu (((sp oh8bmw omjo//z6ncertainties. They cannot both be the smallest, s6((/ n vhqwo(q s/ujpm9b 8z/9eoo jhmo they must 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.