2 blocks each with mass 10kg connected by amassless spring of spring constant 30000N/m and are placed vertically on a hard surface by what minimum amt should the spring be compressed such that if system is released

 

from rest the lower block leaves the surface in the subsequent motion

a)5 b)10 c)2 d)1

hi friend it is a very good Q

i am doing this by work energy theorem

let L be the length

then when it is compressed by a distance x its energy will be

1/2Kx²+mg(L-x)

suppose it has now risen to a height H above its orignal length

then

1/2Kh²+mg(L+H)

equating both of them L will cancel out and

you know to lilift the lower block tention in the spring should be

KH=mg

by replacing these values of H you will get a quadratic in x

and neglect the negative value

 

plzzz rate me i am new to this

bye