Question

An ideal spring with spring constant k is hung from the ceiling and a block of mass M is attached to its lower end. The mass is released with the spring initially unstretched. Then the maximum extension in the spring is
A. Mg/2k
B. Mg/k
C. 2 Mg/k
D. 4 Mg/k

Answer 1

Correct Answer - C
Loss in grav. PE= gain in spring PE
At maximum elongation
`Mgx=(1)/(2)kx^(2)`
`x=(2Mg)/(k)`