[填空题]
The density of a sol+rmrt;5o8 :0jyy8 jjgxxkw t3id sphere is measu8p6r (ubmow,fe c-rd0red with percentage uncertainty of 5%. The radius of the sphere is 4.0 ± 0.2 cm. What is the percent frpdr mco860w( ue-b,age uncertainty in the mass of the sphere? % (Please do not include the % simbol in the blank)
参考答案: 20.0
本题详细解析: The mass of the sphere can be calculated by multiplying its volume by the densita3.2qh4c nnwn y of the material of whichnw 24.nhc an3q it is made: $$M=\frac{4}{3} \pi r^3 \rho$$ so the percentage uncertainty in $M$ is $$\frac{\Delta M}{M}=3 \frac{\Delta r}{r}+\frac{\Delta \rho}{\rho} .$$ The percentage uncertainty in $r$ is $5 \%$, so the percentage error in $M$ is $(3 \times 5 \%)+5 \%=20 \%$