Tension and Normal Force in a Moving Elevator

AI Thread Summary
In a scenario where a 5.0 kg mass is suspended in a decelerating elevator, the normal force is calculated as Fn=mg, resulting in 49 N. The elevator's upward motion is decreasing at a rate of 2.0 m/s², introducing an additional force due to negative acceleration. To find the tension in the string, the total force is calculated as f_total = 49 N - (5 kg * 2 m/s²), leading to a tension of 39 N. The approach combines the effects of gravity and the elevator's deceleration to determine the tension accurately. Understanding these forces is crucial for solving similar physics problems involving moving systems.
patelkey
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A 5.0 kg mass is suspended by a string from the ceiling of an elevator that
is moving upward with a speed which is decreasing at a constant rate of 2.0
m/s in each second. What is the tension in the string supporting the mass?

-I know that the Normal Force on the string is Fn=mg so it would be equal to 49 N, however how would I use the rest of the information to calculate the tension in the string. I know that the answer is supposed to be 39 N but I don't know how to approach it from this point.
 
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2.0 m/s/s means that there is an additional force caused by the deceleration of the elevator (negative acceleration), and F=ma. Therefore f_total = 49N - 5kg*(2m/s^2) = 39N
 
okk that's what I was thinking but I felt as if it was just a guess that happened to work out thanks for the explanation
 

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