[填空题]
The density of a solid -*8lucoupmt6 k xbiviy wf,0e2 **+dssp9helgm/am9y 1 here is measured with percentage uncertainty of 5%. The radm991 ya/helgmius of the sphere is 4.0 ± 0.2 cm. 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 no /oe 3jijwhn8h-wq :8)2ujxbe calculated by multiplying its volume by the density of the material of which it i:-jjqo h88/ohin unw2 )3wxejs 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 $(3 \times 5 \%)+5 \%=20 \%$