(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A mass of 50 kg falls 50 cm onto the platform of a spring scale and sticks. The platform comes to rest 10 cm below its initial position. The mass of the platform is 2 kg. Find the spring constant.

2. Relevant equations

3. The attempt at a solution

I thought of the following solution using conservation of energy:

m*g*h = (k*A^2)/2

leads to k = 1000g

But I also thought of the solution using conservation of momentum:

v0^2=2*a*(ds)=g

m*v0=M*v1 (M is the total mass)

m*v0/M=v1=5*g/6

(m*v1)^2/2=(k*A^2)/2

k = 5000*g^2/3

Could it also simply be that the spring comes to rest when forces are at equilibrium

M*g=k*x

That yields

k=100*g

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Find the spring constant

**Physics Forums | Science Articles, Homework Help, Discussion**