由题意知L1=L2,R1=2R2,M1=M2.(1为甲,2为已)
V1=πR1~2*L1 P1=M1/V1 (以P代表密度)
V2=πR2~2*L2 P2=M2/V2
P1/P2=M1*V2/(M1*V1)
=V2/V1
=πR2~2*L2 /(πR1~2*L1)
=R2*R2*L2/(4R2*R2*L2)
=1/4
1的密度是2的1/4.即,甲的密度是已的1/4.
答案:B
由题意知L1=L2,R1=2R2,M1=M2.(1为甲,2为已)
V1=πR1~2*L1 P1=M1/V1 (以P代表密度)
V2=πR2~2*L2 P2=M2/V2
P1/P2=M1*V2/(M1*V1)
=V2/V1
=πR2~2*L2 /(πR1~2*L1)
=R2*R2*L2/(4R2*R2*L2)
=1/4
1的密度是2的1/4.即,甲的密度是已的1/4.
答案:B