[填空题]
The density of a solsl6x s e /.5;rd1gosb/ pod-y4;gidslid ee0lj(,hr; q4 1xl/ vt 8pwfpssphere is measured with percentage uncertainty of 5%. The radius of the sphere is 4.0 ± 0.2 cm. What is the percentage uncertainty in the massper 1fv h8qt40ls ,pjexw/(l; 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 calculatehji.q;1 ryjfu7 0sx 0ed by multiplying its volume by the density ou q0;0fhri 1 j.jy7exsf the material of which 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 $(3 \times 5 \%)+5 \%=20 \%$