Physics--Spring Constant?

Question

Janet wants to find the spring constant of a given spring, so she hangs the spring vertically and attaches a 0.60 kg mass to the spring's other end. If the spring stretches 3.4 cm from its equilibrium position, what is the spring constant?

Answer 1

Spring constant = force / deflection = (0.60 kg x 9.8 m / sec^2) / .034 m. Spring constant k = 172.9 N/m

Answer 2

The formula to use is

F = kx and since F = mg

mg = kx

and solving for "k",

k = mg/x

where

F = force hanging at the end of the spring

m = mass hanging at the end of the spring = 0.60 kg.

g = acceleration due to gravity = 9.8 m/sec^2 (constant)

k = spring constant

x = spring elongation due to the force = 3.4 cm = 0.0034 m (given)

Substituting appropriate values,

k = 0.60(9.8)/0.0034

k = 1729.41 N/m