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

A moving 2.3kg block collides with a horizontal spring whose spring constant is 258 N/m. The block compresses the spring a maximum distance of 0.09m from its rest position. The coefficient of friction (mu) between the block and the horizontal surface is 0.32. What is the work done by the spring in bringing the block to rest?

2. Relevant equations

delta K=W_{net}and W_{net}=W_{spring}+W_{fric}

delta K=K_{f}-K_{i}where K_{f}=0 because v_{f}=0m/s so delta K=-1/2mv_{i}^{2}

W_{fric}=F_{fk}*deltaX where deltaX=X-X_{e}=X=0.09m because X_{e}=0 for spring at equilibrium

F_{fk}=mu_{k}*mg

m=2.3kg and g=9.8m/s^{2}

3. The attempt at a solution

I believe I need to find W_{spring}so:

W_{spring}=-1/2mv_{i}^{2}- W_{fric}

=-1/2mv_{i}^{2}- mu_{k}*mgX

But I have no clue how to figure out how fast the block was moving initially, v_{i}?? I would use v_{f}^{2}=v_{i}^{2}+2aX but I don't know the acceleration, a, of the block either. I think I could get it from one of the Forces but I don't know which? Any help to point me in the right direction would be greatly appreciated.

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# Homework Help: Work done by spring bringin block to rest

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