[填空题]
The density of a solid sphewablgxa:++9biby1)a q+1n o are is measuredsj8gnz9v932 2h xfo9 txew l5c with percentage uncertainty of 5%. The radius of the sphere is 4.0 ± 0.2 cm. What is the percentage uncertainty in the mass of the sphere? 59wnc2f2h 3te vjo9 sxlz89 gx % (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 volum,xeq kka4(p, jyt3pr )e by the density of the material o k4x)p ,ajyqe,r3t( pkf 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 $(3 \times 5 \%)+5 \%=20 \%$