Question
Tue March 24, 2015 By: R K Jha

You are given a sphere of radius 2 cm.If you are asked to select a best suited spring balance to determine its weight, then what should be the range and least count of the spring balance?(the sphere is made of an alloy of density 7x103  kg/m3).

Expert Reply
Priyanka Kumbhar
Tue March 24, 2015
begin mathsize 12px style Given colon Radius space of space the space sphere comma space straight r space equals space 2 space cm space equals space 0.02 space straight m Density space of space alloy comma space straight d space equals space 7 space cross times space 10 cubed space kg space straight m to the power of negative 3 end exponent density space equals space mass over volume mass comma space straight m space equals space density space cross times space volume space equals space 7 space cross times space 10 cubed space cross times space 4 over 3 πr cubed straight m space equals space space 7 space cross times space 10 cubed space cross times space 4 over 3 space cross times space 3.14 space cross times space left parenthesis 0.02 right parenthesis cubed straight m space equals space 234.43 space cross times space 10 to the power of negative 3 end exponent space kg space equals space 234.34 space gm weight space of space sphere comma space straight W space equals space mg space equals space 234.34 space gwt end style
We can take the range of the weight around 0-250 gwt. So if we consider a balance spring balance with this range its least count will be 2.5 gwt
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