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ld.mclemore
Feb 26, 2012, 09:19 AM
A scale reads 100N when a piece of aluminum is hanging from it. What does it read when it is lowered so that the aluminum is submerged in water?

ballengerb1
Feb 26, 2012, 09:28 AM
It isn't quit that simple. You need to know more about the water. Temp and salt content will alter your reading but always be less than 100n. Bouyancy: Archimedes Principle (http://www.grc.nasa.gov/WWW/k-12/WindTunnel/Activities/buoy_Archimedes.html)

ebaines
Feb 27, 2012, 01:14 PM
All you really need to know is how the density ( \rho) of the water compares to the density of the aluminum. Yes, these densities depend on things like temp (to a small extent) - but I suspect the OP has been given values for these in his/her text book.

The weight registered by the scale will be equal to:

\frac {\rho _{ Al} - \rho _{Water}}{\rho_ { Al}} \ \times \ 100N.