Let B be the point upto which the weighted glass tube is immersed in the liquid such that
l = 20 cm = 0.20 m.
Applying the law of floating,
weight of tube = weight of the liquid displaced = upthrust
∴ mg = (Al)ρg
where m is the mass of the tube, A is cross-sectional area of the tube and ρ is the density of liquid.
m = Alρ = A x 0.20 x p
Let the tube be pushed into the liquid upto point C such that
BC = x
Restoring force = weight of the extra liquid displaced
= Additional upthrust
= - Axρg = - Aρgx
