A bullet to mass 1 kg fired with a speed `2 mn^(-1) ` from x=0 passes through a block of wood whose centre is kept at a distance of 10 m from the origin as shown in the figure.
The retarding force `F_r` on the bullet within the wooden block is -0.5 /x.
The minimum length of the block (upto one decimal digit ) required to completely stop the bullet is ( Assume , `e^4 =55`)

Options

A. 10.1 m
B. 9.2 m
C. 9.7 m
D. 19.3 m

Explanation

The sum of the work done by all the forces acting on a particle is equal to the change in its kinetic energy .
`Delta W = int F * dx = Delta KE`
`rArr int F *dx =1/2 m(v_f^2 - v_i^2)`