An ideal spring of spring constant k, is suspended from the ceiling of a room and a blok of mass m is fastened to its lower end. If the block is released when the spring is un-stretched, then then maximum extension in the spring is :

Options

A. `4( mg)/(k)`
B. `( mg)/(k)`
C. `2( mg)/(k)`
D. `(mg)/(2k)`

Answer

C

Explanation

`T= 2pi sqrt((m)/(k))`
`F=-kx`
`:.x=|-(F)/(k')|=(F)/(k')`
`F= mg and k' =(k)/(2)`
`:. X=(mg)/((k)/(2))=(2mg)/(k)`