# physics

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The cable of a 1800-kg elevator has broken, and the elevator is moving downward at a steady speed of 1.6 m/s. A safety braking system that works on friction prevents the downward speed from increasing.

a. at what rate does mechanical energy turn into thermal energy. I found this:
28.2528 kW

b.While the elevator is moving downward at 1.6 m/s, the braking system fails and the elevator is in free-fall for a distance of 5.3 m before hitting the top of a large safety spring with force constant of 1.50 104 N/m. After the elevator hits the top of the spring, find the distance d that the spring is compressed before the elevator is brought to rest.

• physics -

rate of energy: force*distance/time=mg*velocity

KE of fall+ addedPE= PE spring
1/2 m*1.6^2+mg*5.3+ mg*x= 1/2 k x^2
solve for x

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