Need help with a question on Newtons Law's of Motion.

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Homework Help Overview

The discussion revolves around a problem involving Newton's Laws of Motion, specifically focusing on calculating the tension in an elevator cable as it accelerates upward. The scenario includes an elevator with a total mass of 800 kg and an upward acceleration of 1.0 m/s², with gravity given in feet per second squared.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss drawing a free body diagram to analyze the forces acting on the elevator, including gravity and tension. There are questions about the units of gravity provided and the implications of using feet instead of meters.

Discussion Status

Some participants have offered guidance on the approach to take, emphasizing the importance of understanding the forces involved without providing numerical solutions. Multiple interpretations of the problem setup and unit conversions are being explored.

Contextual Notes

There is a noted confusion regarding the use of feet for the acceleration due to gravity, with participants expressing uncertainty about unit conversions and the relevance of the given values.

nelone
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An elevator is moving upward with an acceleration of 1.0 m/s2. The total mass of the elevator and the passengers is 800kg. I need to find the tension in the elevator cable assuming g=32ft/s2. Need help, beginner in physics. Thanks!
 
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Draw a free body diagram of the elevator and figure out the magnitude of the total force, applied by the cable, that is required to make it accelerate upwards at 1 m/s. That's the tension in the cable.

- Warren
 
nelone said:
An elevator is moving upward with an acceleration of 1.0 m/s2. The total mass of the elevator and the passengers is 800kg. I need to find the tension in the elevator cable assuming g=32ft/s2. Need help, beginner in physics. Thanks!

Forces acting downwards are : Gravity (800g)
Forces acting upwards are : Tension.

Resolving forces and acceleration:
F = ma
T - 800G = 800x1
T = 800 + 800G

I never ever work in feet and can't believe they've given it to you in the form ft/s^2, is this an age old textbook or something? Personally i don't know the feet to m conversion but if gravity is 9.8m/s/s.
T = 8640N
 
Thank you very much
 
KnowledgeIsPower:

Please refrain from giving actual numerical answers to homework problems. It is much more constructive pedagogically to explain the method for solving the problem, but leave the actual numerical solution to the student.

- Warren
 

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