Problem: An elevator cable breaks when a 754 kg elevator is 20.8 m above the top of a huge spring (k = 6.93×104 N/m) at the bottom of the shaft. Calculate the amount the spring compresses (note that here work is done by both the spring and gravity).(adsbygoogle = window.adsbygoogle || []).push({});

i calculated the speed of the elevator just before it hits the spring which is

Vinitial = 20.19 m/s

the equation i used was (1/2)mV^2-(1/2)mVinitial^2= -(1/2)kx^2 + mgx

x is the distance the spring was compressed

and at distance x the current velocity = 0 because it is not moving at all anymore

therefore the equation becomes -(1/2)mVinitial^2= -(1/2)kx^2 + mgx

i plugged in all the numbers and solved by the quadratic equation.. but still came up with the wrong answer...

can someone help?

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# Elevator and spring problem

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