posted by Elisa .
Can't get correct answer
An object weighing 340 N in air is immersed in water after being tied to a string connected to a balance. The scale now reads 260 N. Immersed in oil, the object weighs 290 N.
(a) Find the density of the object.
(b) Find the density of the oil.
The volume of water displaced weighs 80 N, and has a mass of 80 N/g = 8.16 kg. That amount of water occupies 8.16 liters, or 8.16*10^-3 m^3, and equals the volume of the object. So the object's density is
[340 N/g]/8.16*10^-3 m^3
= 4250 kg/m^3
The weight reduction in oil is 5/8 of the weight reduction in water, so the oil has 50/80 of the density of water, or 625kg/m^3