[填空题]
The density of a solid spherp du3xs zy9h. *-adwf1e is measuwt*ju2xv/ qu8 e7r t0nv2e b,zred with percentage uncertainty of 5%. The radius of the 7 ,/xt2tvubz qne* 0w8ur2vjesphere 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 be calculated by multiplying its volume by th6jg lyy8xdh 4bpho0/*e density of they /hj6d xoy4h0*blg p8 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 $(3 \times 5 \%)+5 \%=20 \%$