2. a rectangular barge 7 m long and 2 m wide floats in fresh water. how much will the barge sink when loaded with 600 kg of sand? show all calculations leading to an answer.

What makes any object float ?
The object displaces an amount of water that has
the same weight as the floating object.

The heavier the object is, the more water it has to displace
in order to float.

The barge is originally floating, so we know that it must be displacing
its own weight in water.

Then somebody comes along and dumps another 600 kg onto it.
Now suddenly, the barge is heavier.  So in order to keep floating,
it has to displace some more water.

However much the extra 600 kg weighs, it has to displace 600 kg
of water.

We're really happy that the whole thing is happening in water, because
that makes the calculation easy ... 1 kg is the mass of 1 liter of water !
With the added load, the barge has to displace 600 more liters of water.

Well, there are 1,000 liters in 1 cubic meter ... 600 liters = 0.600 meter³ .
The barge has to settle a little lower in the water, just enough to displace
another 0.6 m³ of water.

As the barge groans and settles deeper in the water, how much new
volume of water does it displace ?

            Extra Volume  =  (length) x (width) x (extra distance it sinks) .

It needs to displace 0.6 m³ of extra volume.

                         0.6 m³ = ( 7 m ) x ( 2 m ) x (extra distance it sinks)

Divide each side
by (7m)x(2m):      0.6 m³ / (7m x 2m) = extra distance it sinks

                             Additional depth =  0.6 m³ / 14 m²

                                                         =  0.0429 meter

                                                         =    43 millimeters  (rounded)
Is that cool or what ? !

Sorry i don’t know what to do

Ibelieve the answer is b