Kinetic energy of massless spring

AI Thread Summary
The discussion revolves around calculating the maximum kinetic energy of a 2.0kg mass on a massless spring compressed 42cm. The potential energy stored in the spring, calculated using U=mgh, is converted entirely into kinetic energy upon release. The conservation of energy principle is applied, equating potential energy to kinetic energy (E_k = E_p). Participants clarify that the potential energy found is indeed equal to the maximum kinetic energy of the mass. The key takeaway is that the potential energy calculated directly translates to kinetic energy when the spring is released.
Flinthill84
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Alright I'm having a little trouble on this one...

One end of a massless spring is welded to a flat surface; the other end points upward. A mass of 2.0kg is set on top of the spring. The spring is then compressed by hand so that the end of the spring is 42cm lower than the position of the spring with no mass on top. The spring is then seddenly released. What is the maximum kinetic energy of the 2.0kg mass??

I think i use the formula KE=1/2mv^2, if that is true could anyone give me a hint on how to find the velocity please? Thankyou!
 
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The spring will have some potential energy. This potential energy will all be converted into kinetic energy for the block. You need to find out how much potential the spring has.
 
ok so the potential energy would be U=mgh which would be (2.0kg)(9.8m/s^2)(-0.42m)...but I guess I still don't understand how this plays into the kinetic energy?
 
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^ conservation of energy? every joule of potential energy being converted into kinetic energy.

just equate E_k = E_p
 
so mgh=1/2mv62 and then I could solve for v and finally solve for kinetic energy?? Or are you saying that the amount of potential energy that I found is the amount of kinetic energy?
 
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