posted by romeo .
a piece of wood 50 cm long , 20 cm wide, 40 cm thick. its density is 0.6 g cm^3. this is connected to a string with negligible mass attached to a piece of lead. what is the mass of the lead and what volume underneath is needed to sink the wood in calm water so that its top is just even with the water level.
VOLUME OF WOOD: .2*.5*.4 M^3=.04 M^3
MASS OF WOOD: .04*6e6 GRAMG=.024e6G=24000grams
now, to sink that block, you need a total mass of .04m^3*1Eg/m^3=40,000 grams, so the mass of lead then is 40-24 kg of lead
check my thinking