Q.
A ball falling in a lake of depth 200m shows 0.1% decrease in its volume at the bottom. What is the bulk modulus of the ball material ? (Take density of water =1000kg/m3 )
When strain is small, the ratio of normal stress to the volume-strain is called the bulk modulus of the material of the body. K=ΔV/Vp
where p is pressure (=AF), and VΔV the change in volume
Given, ΔV=0.1%,V=0.001 volt, p=hρg p=hρgp=200×1000×9.8 =1.96×106N/m2 ∴K=0.0011.96×106 =19.6×108N/m2