Solving the Spring-Weight Paradox: 0.039m

[Speedking96]

Homework Statement

Homework Equations

Fs = -kx

w = mg

The Attempt at a Solution

I said that when the spring is stretched out at its max, the weight pulling down will equal the force of the spring pulling up.

Fs=w
-kx = mg
-(1500)(x) = (3)(-9.81)

x = 0.01962 m

The solution key tells me the max stretch is double this amount, 0.039 m. What is wrong with my approach?

 

[BvU]

Mark the word suddenly. If the basket were at maximum distance and forces would be in equilibrium, the velocity wouldn't change anymore, so the thing would hang still.
Do you think that is what would happen if you suddenly put a brick in the basket ?

 

[Speedking96]

Ah. I see. So then I need to solve the problem using the conservation of energy.