which is right?

Question

i have asked this question and recieved many different answers:

An elevator has a mass of 900kg, at most it uses a force which is equivalent to 17kN. How many people who weigh 75kg can the elevator maximum take?

http://answers.yahoo.com/question/index;_ylt=AkTtEbFTcQsvI1mp2zXgu3Tsy6IX;_ylv=3?qid=20071109074401AAx8atq

which one is right and why?


thanks for your time.

Answer 1

On the first question, "T" and "Lee W" both solved the problem correctly. It's just that Lee W used a less accurate approximation for the acceleration of gravity: He used 10 m/s^2 for gravity instead of 9.81 m/s^2. (That's 1 versus 3 significant figures). Sometime accuracy counts.

So T had the best answer because he solved the problem to 3 significant figures (11.11) instead of Lee W who solved it to 1 significant figure (10.67 which technically rounds up to 11, but Lee W rounded down on the side of caution). If Lee W had used 9.81 as the force of gravity, he would have gotten the same answer as T.

The first guy on the original question was an idiot. "Plz help," above, also did it right

Answer 2

The correct answer is 11.11 or 11 people let me show you. The elevator can hold 17kN or 17000 N or 1734.69 kg. So now subtract the amount of the weight of the elevator which is 900 kg and you get 834.69 kg and now divide by 75kg for each person's weight and you get 11.11 or 11 people.