Force question on elevator cable

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Homework Help Overview

The discussion revolves around a physics problem involving forces acting on an elevator that is accelerating upwards. The original poster presents calculations related to the forces exerted by the cable and the gravitational force acting on the elevator.

Discussion Character

  • Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate the total force exerted by the cable, presenting various force components but lacks clarity in labeling them. Some participants question the accuracy of the labels used for different forces and suggest clearer definitions.

Discussion Status

Participants are actively engaging in clarifying the definitions of forces involved, with some providing feedback on the original poster's calculations. There is a constructive exchange regarding the correct representation of net force, gravitational force, and tension in the cable.

Contextual Notes

The problem is constrained by the requirement to use specific values for mass and gravitational acceleration, and there is an ongoing discussion about the correct labeling of forces without reaching a final consensus on the presentation of the solution.

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A 700 kg elevator suspended by a cable accelerates upwards at 3 m/s^2. The force exerted by the cable on the elevator is?
(use g=10 m/s^2)

m=700 kg
a= 3.0 m/s^2

Fnet= 700 kg * 3.0 m/s^2
= 2,100.0 N Upward force

Fnet= 700 kg * 10 m/s^2
= 7,000.0 N Downward force

Fnet= 2,100.0 N + 7,000.0 N = 9,100.0 N

So is 9,100.0 N the total force exerted on the cable?
 
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Yes, but you didn't express that very well. All of those different numbers can't be Fnet. One of them is Fnet=ma, one of them is gravitational force and one is the cable tension. Can you label them correctly?
 
Fnet= 700 kg * 3 m/s^2
= 2,100.0 N

Fg= 700 kg * 10 m/s^2
= 7,000.0 N

T= 2,100.0 N + 7,000.0 N
= 9,100.0 N

What is the variable for tension. I am not sure so I just used T.
Would this be a more suitable answer?
 
Better. Fnet is the sum of all forces. Fnet=T-Fg. So yes, T=Fnet+Fg.
 
Thanks a lot. Appreciate your help.
 

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