12.61 . An open barge has the
dimensions shown in Fig. P12.61.
If the barge is made out of 4.0-
cm-thick steel plate on each of
its four sides and its bottom,
what mass of coal can the barge
carry in freshwater without sink-
ing? Is there enough room in the barge to hold this amount of coal? 1The density of coal is about 1500 kg>m3.2