In: Physics
13. A barge floating in fresh water (Q= 1000 kg/m3) is shaped like a hollow rectangular prism with base area A=550 m2and height H= 2.0 m. When empty the bottom of the barge is located H0= 0.45 m below the surface of the water. When fully loaded with coal the bottom of the barge is located H1= 8 m below the surface.
a)
b)
Ho = height of the empty barge below the water surface
Q = density of fresh water
A = area of the base of the barge
Volume of water displaced is given as
V = A Ho
Fb = force of buoyancy on the empty barge
force of buoyancy on the empty barge is given as
Fb = Q V g
Fb = Q (A Ho) g
Fb = Q A Ho g
c)
M = mass of the barge
Using equilibrium of force along the vertical direction , we have
Fb = Fg
Q A Ho g = Mg
(1000) (550) (0.45) = M
M = 247500 kg
d)
e)
m = mass of the coal
H = height of the barge inside water
Q = density of fresh water
A = area of the base of the barge
Volume of water displaced is given as
V = A H
Fb = force of buoyancy on the loaded barge
force of buoyancy on the loaded barge is given as
Fb = Fg + Fg'
Q A H g = Q A Ho g+ mg
m = (Q A) (H - Ho)
f)
m = (Q A) (H - Ho)
m = ((1000) (550)) (2 - 0.45)
m = 852500
g)
m = (Q A) (H1 - Ho)
350000 = ((1000) (550)) (H1 - 0.45)
H1 = 1.086 m