A crane with a steel cable of length 11 m and radius 2.0 cm is employed to lift a block of concrete of mass 40 tons in building site. Young's Modulus of steel is `2.0 xx 10^(11)` Pa, what will be roughly the increase in the length of the cable while lifting the block ? (Take g = `10 ms^(-2)`)

Options

A. 0.75 cm
B. 1.25 cm
C. 1.75 cm
D. 2.50 cm

Answer

C

Explanation

`Deltat=F/A.L/Y=(40xx1000xx10xx11)/(pi.(0.02)^(2)xx2xx10^(11))`
`=(4xx11)/(pixx4xx2)xx10^(-2)=1.75xx10^(-2)m`
`=1.75cm`
So correct choice is (c).