# If the length of a 48 cm spring increases to 93 cm when a 6 kg weight is hanging from it, what is the spring's constant?

The length increases from $0.48$ $m$ to $0.93$ $m$. The force acting is the weight force, $F = m g = 6 \cdot 9.8 = 58.8$ $N$.
Then $k = \frac{F}{x} = \frac{58.8}{0.93 - 0.48} \approx 130.7$ $N {m}^{-} 1$ (or $k g {s}^{-} 2$).