# If the length of a 2 cm spring increases to 6 cm when a 3 kg weight is hanging from it, what is the spring's constant?

Feb 28, 2016

$k = 7.35 k g {s}^{-} 2$

#### Explanation:

Given that change in extension of spring is $\delta x = 4 c m = 4 \cdot {10}^{-} 2 c m$. Mass added to spring is $m = 3 k g$. Since this is happening on a vertical spring, $a = g$.

So, $k x = m g \setminus \implies k = m \frac{g}{\delta x} = 3 \cdot \frac{9.8}{4}$