Question

Say you have an object with a volume of 1.5 m^3, a density of 800 kg/m^3, and a mass of 1200 kg. You place this object in a tank of water. The gravitational force is 11760 N, and the buoyant force is 14700 N. The net force is then 2940 N, and the object will float/rise to the surface.

How do you determine what percent of the object will remain submerged in the water?

If someone could explain how to do this for me, and walk me through it, I would greatly appreciate it.

Answer 1

normal Archimedes principle: bouyant force = weight of displaced fluid.

the key in in the special case of where a body floats is to recognise that it follows that **the floating body displaces its own mass/weight of the fluid in which it floats**.

this must be true because in this case the bouyant force = weight of floating object.

thus, if 1200kg of water = 1.2m^3 is displaced, then 1.5 - 1.2 = 0.3 m^3 of the floating body must be above water....

is that a good start?

Answer 2

when the volume of water displaced is equal in weight to object seems familiar to me.

Answer 3

weight of the volume ....

Answer 4

I'm sorry, I'm still a little confused. Can you explain it in more detail? I don't want the answer, I just want to understand so I can solve it myself.

Answer 5

Actually, I think I've got it now. Thank you so much!

Answer 6

cool.

years ago, i actually placed to memory the words i put in ***'s simply because it is so handy not to have to work from Archimedes principle to the rule that applies to floating bodies.