Weight of body in air, m1=50g=5×10−2kg Weight of body in water, m2=40g=4×10−2kg Buoyant force on the body, F′=m1g−m2g =g(m1−m2) =g(5×10−2−4×10−2) F′=10−2gN . . . (i) But buoyant force is given as F′=Vρg ⇒10−2g=Vρg [From Eq. (i)] ⇒10−2=ρV 10−2=103V[∵ρ=103kg∕m3] ⇒V=10−5m3 ∴ Loss of weight in liquid =ρlVg W′=1.5ρ×10−5×10[∵ρl=1.5ρ] =1.5×103×10−5×10 =0.15N ∴ Loss of weight ( in kg)=
w′
g
=
0.15
10
=0.015kg=15g ∴ Weight of body in water =50−15=35g