A cell phone, when weighed in air has a weight of 5.5 newton. When completely immersed in water, however, it has a weight of 3.3 newton. Find the volume of the cell phone.

Answer 1

Let P = 5.5 N, G= 3.3 N
Buoyancy force F= P - G or according to the definition
F= Mg= D•V•g.
where D is the density of water.
P - G = D•V•g,
V = (P – G)/D•g =(5.5-3.3)/1000•9.8 =2.24•10^-4 m^3