Question

An object with a mass of `3` `kg` is hanging from a spring with a constant of `8` `kgs^-2`. If the spring is stretched by `3` `m`, what is the net force on the object?

Answer 1

The net force acting the difference between the weight force, `F=mg`, acting downward and the spring force, `F=kx`, acting upward. The net force is `F=mg-kx` (if we define downward as positive). `F=3xx9.8-8xx3=5.4` `N` downward.