# If the length of a 35 cm spring increases to 73 cm when a 3 kg weight is hanging from it, what is the spring's constant?

Dec 13, 2015

The spring constant will be $- 3 \frac{N}{m}$

#### Explanation:

Given Data:

$D i s p l a c e m e n t \left(x\right) = 73 c m - 35 c m = 38 c m$
$= 38 \cdot {10}^{-} 3 m$
$x = 0.38 m$

We've just done this to get it into the SI units or MKS system.

Force (F) $= m \cdot a = 3 \cdot 0.38$
$F = 1.14 N$

Spring Constant (k) = ?

We know:

Spring Constant (k) $= - \frac{F}{x}$

$k = - \frac{1.14}{0.38}$

$k = - 3$