A person weighing 490 N steps on a scale in an elevator?
A) What does the scale read when the elevator is rising at a constant velocity?
B) The elevator slows down at 2.0 m/s^2 as it reaches the desired floor. What does the scale read?
A) What does the scale read when the elevator is rising at a constant velocity?
B) The elevator slows down at 2.0 m/s^2 as it reaches the desired floor. What does the scale read?
Deepesh Singh
Favorite Answer
One of my favorite concepts.
Let try.
As we all know that earth attracts all particle with a force mg which becomes its weight. Now
A) Here the velocity is constant, so acceleration will be zero, no external force. That's why the weight wont change. Weight will remain 490 N
b) retardation of 2.0 m/s^2, means if object is moving upward the force will act in downward direction, which will add to g. So commutative g becomes 9.8 + 2 = 11.8 m/s^2
Now weight= m(g+a)-------------1
We know that mg=490N => m = 490/g
Put the value of m into equation 1, we get
Weight= 490/g * (11.8) N
> Weight= 590 N
For better understanding.
http://www.flickr.com/photos/72927043@N07/8189535771/in/photostream
Thank You!
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Anonymous
you're plugging in 490 as kilograms, that's mass, somewhat of Newtons(N) that's stress. A scale does degree stress, no longer mass, even if the kilogram scale on the dimensions assumes time-honored gravity and does the mathematics for you. So, take F=ma and rearrange it to m=F/a, with a being time-honored Earth gravity. So 490N/(9.8m/s^2)=50kg. For the following questions, the elevator's acceleration elements to or subtracts from gravity. attempt that, acceptable your solutions, and that i will take a seem back. i'd nonetheless favor to get your as a lot as date solutions to work out once you're operating some thing of the placement properly (like including accelerations somewhat of multiplying them).