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

An elevator is traveling at 30 m/s just as it touches a cushioning spring. The safety clamps engage at that moment and provide 20,000N of frictional force. The mass of the elevator is 3000kg and the spring constant is 15000 N/m. How fast will the elevator be traveling after the spring compresses 0.8m ?

2. Relevant equations

K_{1}+W_{f}= U_{g2}+U_{s2}+K_{2}

Allow the point that the elevator touches the spring to be y=0

3. The attempt at a solution

1/2*m(v_{1})^{2}+F_{f}d=mgy_{2}+1/2*kx^{2}+1/2*mv_{2}^{2}

Manipulating this around and plugging in numbers gives an answer of 30.03 m/s for me. Am I missing something here?

Edit: d is just the distance along which friction occurs, -.8 m?

x is the compression of the spring, also .8m

y_{2}is the distance traveled by the elevator, so -.8m

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Energy Problem with Spring, Gravity, and Friction

Have something to add?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**