How Do Buoyant Forces Affect Submerged Objects?

[dragon162]

Homework Statement

note: It may make things easier to assume that g=10 m/s^2
Suppose that I have a 100 gram chunk of metal with a density of 4 grams per cubic centimeter.
1)What is the mass of water displaced by this chunk of metal?(give your answer in kg)
2)what is the buoyant force on the metal?
3)If I hang this 100 gram chunk of metal from a spring scale and lower the metal into the water what will the scale read?(give your answer in Newtons)

Homework Equations

d=m/v
S=W/(W-W_0)
S=W/(W_1-W_2)

The Attempt at a Solution

For number one I am guessing its just a simple d=m/v problem. So given the information V=0.1kg/.004 kg/cm^3= 25. But i am not sure what to do with this after.

For number two I know that the difference of the weight of the object in the air and the weight of the object when its fully submerged in water is the buoyant force exerted on the body by the water. So to get the W=mg=.1kg*10m/s^2 but i am not sure how to get W_1= the weight of the object in the water.

for part three I am just not sure what I am supposed to do.

 

[dragon162]

ok so i figured out for part two that the volume of the object is the same as the volume of the displaced water. so using the v olume i calculated i used m=dv=25(1)=25 to get the mass of the water. This correct?

as for part two, i found out that the buoyant force= to the weight of fluid displaced and to find the weight of fluid displaced its just volume of object* density of the fluid*gravity
so 25*1*10=250. Is this correct as well?

still trying to figure out part three so any help would be appreciated.

 

[dragon162]

bump, some help please