# An object with a mass of 4 kg is hanging from a spring with a constant of 2 kgs^-2. If the spring is stretched by 4 m, what is the net force on the object?

There are two forces acting, a downward weight force $F = m g = 4 \times 9.8 = 39.2$ $N$ and an upward restoring force, $F = k x = 2 \times 4 = 8$ $N$. The net force is therefore $35.2$ $N$ downward.
(insert my usual grumble about the fact that, despite the fact that they are equivalent, $N {m}^{-} 1$ is a much more sensible unit for the spring constant than $k g {s}^{-} 2$!)