An iron piece of mass 360g and a density of 6g/cm^3 is suspended by a rope so that is partially (halfway)in oil of density 0.9 g/cm^3.Find the tension (force) in the string.

Question

An iron piece of mass 360g and a density of 6g/cm^3 is suspended by a rope so that is partially  (halfway)in oil of density 0.9 g/cm^3.Find the tension (force) in the string.

bobpursley · Accepted Answer

find volume submerged:
1/2 * mass/density=1/2 * 360*1/6=30cm^3 check that.

Now mass loss due to submerged:
volumesuberged*densitywater=30cm^3*.9=27g

tension= mg-mg ofdisplaced fluid
= .06*9.8 -.027*9.8 N= .323 Newtons

check that