Tension and Normal Force in a Moving Elevator

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SUMMARY

The discussion centers on calculating the tension in a string supporting a 5.0 kg mass in an elevator that is decelerating at a rate of 2.0 m/s². The normal force acting on the mass is calculated as Fn = mg, resulting in 49 N. However, due to the elevator's negative acceleration, the effective tension in the string is determined using the formula F_total = Fn - ma, leading to a final tension of 39 N. This calculation illustrates the impact of deceleration on tension in a moving system.

PREREQUISITES
  • Understanding of Newton's Second Law (F=ma)
  • Knowledge of normal force calculations (Fn=mg)
  • Familiarity with concepts of acceleration and deceleration
  • Basic grasp of forces in a moving reference frame
NEXT STEPS
  • Study the effects of acceleration on tension in different scenarios
  • Explore advanced applications of Newton's Laws in non-inertial frames
  • Learn about free-body diagrams for complex systems
  • Investigate the relationship between mass, weight, and tension in various contexts
USEFUL FOR

Physics students, educators, and anyone interested in understanding dynamics in non-inertial reference frames, particularly in scenarios involving tension and forces in 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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