steel boat...?

Question

the bottom of a steel boat is a 5 m x 10m x 2 cm piece of steel (rho steel 7900 kg/m^3 ) the sides are made of 0.50 cm thick steel. what minimum height must the sides have for this boat to float in perfectly calm water??

plzz guys i need help.....could u explain it ...thanks

the answer should be 14 cm....im using
rho ave= mass of the bottom/ area of the bottom x the height of the sides < density of water.......so in order to float.....h=m/rho A

Answer 1

For an object to float it must displace a volume of water equivalent to the weight of the object.

First, calculate the mass of the object to float.

In this case, the keel, or bottom, has mass
=7900*5*10*2/100
=7900 kg

There will be four sides. I will assume that the sides will be attached such that the 2cm keel is below the sides. This way the volume of the vessel will be
5*10*(0.02+h)
or 50*(.02+h)

The mass of the sides will be
7900*h*(5+5+10+10)*0.50/100
=1185*h

therefore
1185*h+7900=50*(.02+h)*1000
This assumes the specific gravity of water is
1000 kg/m^3
1185*h+7900=50000h+50000*.02
h=6900/(50000-1185)

h=14 cm

j

Answer 2

bouyancy calc man!

the weight of the water displaced (volXwt) and the weight of the steel.......

if the weight of the steel is less that the vol displaced

then it floats!!!!!!

oh I forgot, is this fresh or salt water?

remember volXwt of water vs weight of steel

more equals FLOAT!!!!