An object of mass 50 g floats in a liquid of density 2.5 g/ml. When the object is placed in a liquid of density 2.0 g/ml, it sinks to the bottom of the container. What is the force that the object exerts on the bottom of the container?

Question

[g = 10m/s^2 = 10N/kg]

Answer 1

Its density must be 2.5g/cc., so its volume must be (50/2.5) = 20cc.
Mass = 50g., = 0.050kg.
(.050 x 9.8) = weight of 0.49N.
When sunken in the 2g/ml. fluid, it will displace 20cc. of it.
The fluid's mass will be (20 x 2) = 40g., = 0.040kg.
(.040 x 9.8) = 0.392N.
Force on bottom = (0.49 - 0.392) = 0.098N.