(1)由杠杆平衡的条件可得,
FA×OC=GB×OD
FA=
×GB=OD OC
×0.5kg×10N/kg=10N;2 1
∵p1:p2=3:1,P=
F S
∴
=GA
GA?FA
=p1 p2
3 1
故GA=15N;故A错误.
(2)mA=
=GA g
=1.5kg.15N 10N/kg
ρA:ρB=
×mA vA
=vB mB
×1.5kg 2
=3:2;故B错误;1 0.5kg
(3)将物体浸没在水中时,因为VA=2VB,所以A受到的浮力是B受到浮力的2倍,
∵10N×OC=5N×OD
∴(15N-2F)×OC>(5N-F)×OD
因此C端会下沉;故C错误;
(4)FC×OC=(GB+2.5N)×OD
FC=7.5N×2=15N=GA.故D正确.
故选D.