A piece of metal of 2kg-wt is suspended from one end of a vertical wire whose end is fixed and the piece is fully immersed in an oil od density 0.7*1000 kg/m3 .The length of the wire increases by 1mm.If the diameter of the wire is 0.6mm,Y=2*1011 & the volume of the metal piece is 800cm3,then calculate the initial length of the wire.
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1 Answers
1In this problem use Y= stress/ strain.
Stress= deforming force/ area
Deforming force= weight of the body - upthrust of oil
upthrust = weight of displaced oil =vol of displaced oil x density x 'g'
Wt. of the body given in kgwt so upthrust = vol x density of oil in kg-wt.
vol of oil displacd = vol of solid.
Cross Sectional Area of wire can be calculated from the diameter given
Strain = change in length / initial length
Since Y is given so you will be able to calculate now