Question

Janet wants to find the spring constant of a given spring, so she hangs the spring vertically and attaches a 0.47 kg mass to the spring's other end. if the spring stretches 3.1 cm from its equilibrium position, what is the spring constant? 133 incorrect: your answer is incorrect. n/m

Answer 1

The stretch of the spring is 
x=3.1 cm=0.031 m
while the force applied to it is the weight of the mass:
$F=mg=(0.47 kg)(9.81 m/s^2)=4.61 N$

So, the spring constant can be found by using Hook's law:
$k= \frac{F}{x}= \frac{4.61 N}{0.031 m}=148.71 N/m$