Friction/Springs/HELP!(adsbygoogle = window.adsbygoogle || []).push({});

An object of mass m=2.6 kg is travelling on a horizontal surface. The coefficient of kinetic friction between the object and the surface is µk=0.16. The object has speed v=0.65 m/s when it reaches x=0 and encounters a spring. The object compresses the spring a distance d/2, stops instantaneously, and then travels back to x=0 where it stops completely. Eventually you will be asked to find the spring constant, k.

1.What is the total distance, d, that the object moves after first touching the spring?

2.When the object reaches d/2 and stops instantaneously, what is the energy stored in the spring?

3.What is the spring constant, k, of the spring?

I just tried to post w/ my entire attempt at a soln ad somehow lost it- so heres a quick version.

1. I got this correct- Wfriction=mv^2/2=-mgukd, solve for d gives correct answer

2. KEspring+Espring=KEi+ Wfriction

Espring= KEi- KEspring+Wfriction=.5mv2-0-mgukd

not correct answer, this is where I feel very confused

3. Espring=-k*d ???

DO I have to use Kf+Uf+deltaEth=Ki+Ui+Wext to solve this problem beacuse friction is non-conservative... if so how?

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# Homework Help: Physics springs and friction

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