The true mass of a rock is 10g. When submerged in water (D=1000kg/m3) the apparent mass of the rock is 5g.
What is the density of the rock?
Please help me with this question? Thanks!!!
Let's say force = F; b= buoyancy, w=weight
On the object, the overall force is Fnet;
Fnet = Fb - Fw;
Fw= mass * g = 0.01 kg * g (pointing down)
Fnet is related to the apparent mass = 0.005 kg* gravity (pointing down)
Fb = the force of buoyancy is the weight of the water displaced =
= mass of water * g (pointing up)
Cancel out gravity in all terms ==> -0.005 kg = Masswater - 0.01 kg
Mass of water is 0.005 kg; Use density to get vol of water, 5e-6
which gives volume of rock; 0.01 kg / vol of rock = density
Nevermind: I did most of it right, I just forgot that the net force is pointing down, so Fnet should be negative.