What Mistakes Are in the Elevator Problem Calculation?

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The discussion identifies errors in the proposed solution for calculating the force exerted by the cable on a descending elevator. The acceleration during deceleration is incorrectly calculated as 6.0 m/s² instead of the correct value of 12.0 m/s², derived from the kinematic equation. Consequently, the tension in the cable should be recalculated using the correct acceleration, leading to a different force value. Additionally, it is emphasized that gravitational force continues to act on the elevator during deceleration, which must be included in the final force calculation. Accurate application of physics principles is crucial for determining the correct force exerted by the cable.
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Identify any errors in the solution to the following problem and provide a corrected solution if there are errors.
The problem A 1000kg elevator is moving down at 6 m/s. It slows to a stop in 3 m as it approaches the ground floor. Determine the force that the cable supporting the elevator exerts on the elevator as the elevator stops. Assume that g = 10N/kg.

Proposed solution The elevator at the right (picture) is the object of interest. It is considered a particle, and the forces that other objects exert on the elevator are shown in the free body diagram (T == F_e) The accelration of the elevator is:

a = v_0^2 / 2d = 6^2 / 2(3) = 6.0 m/s^2
The force of the cable on the elevator while stopping is:

T = ma = (1000kg) * (6.0 m/s^2) = 6000N
 
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