Two blocks are attached to each other. The mass of the first block is 80.0kg and its density is 1071 kg/m^3. The density of the second block is 120 kg/m ^3.
What is the volume of the second block if the arragement is barely afloat in water?
2007-10-14 13:52:45 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Density is m/v. You can find the volume of the first block using algebra. The density of water is 1000 kg/m^3. The first block has negative density due to its being more dense.
Using the 1st block's density and the volume, you can find how much more mass (kg ) it has than the water it displaces. Then from
W = m*g
you can find the net force trying to pull it under. (You don't actually have to calculate W out. Note what happens next.)
The 2nd block needs to displace enough water that it has that same number of kg fewer than the water it displaces. Then the 2nd block has positive buoyancy to offset the 1st block's negative buoyancy.
Another way to look at this: the total mass of the 2 blocks divided by their total volume needs to be the same density as water.
2007-10-14 14:46:36 · answer #1 · answered by sojsail 7 · 0⤊ 0⤋