A block of mass `2kg` is attached with a spring of spring constant `4000Nm^-1` and the system is kept on smooth horizontal table. The other end of the spring is attached with a wall. Initially spring is stretched by `5cm` from its natural position and the block is at rest. Now suddenly an impulse of `4kg-ms^-1` is given to the block towards the wall.
Approximate distance travelled by the block when it comes to rest for a second time (not including the initial one) will be (Take `sqrt(45)=6.70`)
Displacement of the rod by the time the insect meet the moth is

Options

A. (a) `L/2`
B. (b) `L`
C. (c) `(3L)/(4)`
D. (d) zero

Answer

D

Explanation

`p_i=p_f`
`:. 0=(8m)(2v)-(16m)(v)+(48m)v^'`
Here `v^'=` absolute speed of rod
`=0`
`:.` Displacement of rod=0`