[填空题]
The density of a solid9;gb,g,qhc) jcixl n ; sphere3 f8:e ka1zoql is measured with percentage uncertainty of 5%. The radius of the sphere is 4.0 ± 0.2 1kea:q 8ofzl3cm. What is the percentage 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 multl.e6zex6m+tb46j qo ,;qn9tjlw* oqriplying its volume by the density of the material of which it ejobl xjqt+,66z46*ro; .l9wnqe mqtis 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 $(3 \times 5 \%)+5 \%=20 \%$