某同学用弹簧秤和一大盆水进行试验,测定正方体金属块的体积.具体方法是：先将弹簧秤调零,再将金属块自由悬挂在弹簧秤挂钩上,

F浮=G-F=0.81N-0.54N=0.27N
V=F浮/p水g=0.27N/1000kg/m3*10N/kg=0.000027m3
a=三次根号V=三次根号0.000027m3=0.03m
S=a^2=0.0009m2
P=F/S=G/S=0.81N/0.0009m2=900Pa