# If the length of a 25 cm spring increases to 79 cm when a 5 kg weight is hanging from it, what is the spring's constant?

##### 1 Answer
Feb 10, 2016

$K = 90 , 83 \frac{N}{m}$

#### Explanation:

$\Delta x = 79 - 25 = 54 c m = 0 , 54 m$
$F = - K \cdot \Delta x$
$5 \cdot 9 , 81 = - K \cdot 0 , 54$
$K = \frac{49 , 05}{0 , 54}$
$K = 90 , 83 \frac{N}{m}$