Question

An object weighing 325 N in air is immersed in water after being tied to a string connected to a balance. The scale now reads 250 N. Immersed in oil, the object weighs 275 N.
(a) Find the density of the object.
(b) Find the density of the oil.

Answer 1

water pushes up with (325-250) = 75 N
density of water =1000 kg/m^3
buoyancy = rho g v
75 =1000*9.8 * v
v = .00765 m^3

density = mass/volume = (325/9.8)/.00765
= 4333 kg/m^3

rho oil * 9.8 * .00765 = (325-275)
rho oil = 667 kg/m^3

Answer 2

325-250=75
325/75 = v/1000
325*1000/75= v
V=4333kg/m’3

Answer 3

An