re: #151 zombie

I had to check back. I had a feeling you’d be typing.

You are absolutely right in what you said about enrgy, and if you keep that in mind, it’s a great way to see the relationship between force and energy.

But I am asking about this in terms of force.

Energy does not come and trump force to make the apparent force contradiction disappear.

When you coil the spring, it has a force that it wants to push because it is coiled. One end pushes the Earth and the other pushes the block.

So put that together with the fact that the block masses much less than the Earth - which was the really hard part of this.

When the spring supplies force to accelerate the block up and the Earth down, what happens to the block (and the spring) if the spring is not attached to the Earth?