Question

An object with a mass of `7 kg` is hanging from a spring with a constant of `2 (kg)/s^2`. If the spring is stretched by `8 m`, what is the net force on the object?

Answer 1

`P.E=1/2 kx^2`

`=1/2*64*2`

`=64` Joule
TOTAL FORCE ACTING `=mass*g`
`=70N`

WORK DONE =`F*S`
THEREFORE `64=F*8`
`F=8N`

NET FORCE`=70-8=62N`