An elevator mass of 7700 kg falls from a height of 32 m after a sudden failure in the hoisting cable. the mass is stopped by a spring at the bottom of the shaft. determine the spring constant (in kn/m) necessary to bring the elevator and occupants to rest without exceeding an acceleration of 5 g's.

k=28.29 kN/m

Explanation:

Given

mass

height from which Elevator falls

Let x be the compression in the spring

thus From conservation of Energy Potential energy will convert in to Elastic Potential Energy of spring

----------1

also maximum acceleration is 5g

thus

here

Substitute x in equation 1

nec chapter 5 contains

c. information on special occupancy areas

nec chapter 6 covers

a. special equipment

which of the following rules contain the words shall or shall not and must be adhered to?

b. mandatory rules

which of the following rules identify actions that are allowed but not required and typically cover options or alternative methods?

c. optional rules

which of the following serves as the introduction to the nec and provides an overview of the book?

a. nec article 90

organizations that test products for safety are

c. nrtls

the nec is published by the

a national fire protection association

the nec is divided into

b. 9 chapters

the nec provides informative annexes for

c. informational materials and examples

two terms from nec article 100 that trainees should become familiar with are

b. labeled and listed

explanation: