Calculating Strain in a Slowing Elevator Cable

  • Thread starter Thread starter Tycho
  • Start date Start date
  • Tags Tags
    Elevator Strain
AI Thread Summary
To calculate the strain in the elevator cable when it is brought to a stop, the total mass supported by the cable is 4110 kg (1260 kg for the elevator plus 2850 kg for the crowd). The force exerted on the cable can be determined using the impulse-momentum principle, considering the change in momentum over the stopping time of 0.600 seconds. The diameter of the cable is relevant for calculating its cross-sectional area, which is necessary for determining stress and subsequently strain. The user is seeking clarification on how to incorporate the deceleration of the elevator into the strain calculation, as they have only calculated strain for constant velocity. Understanding the initial velocity and applying the correct equations of motion will be essential for solving this problem.
Tycho
Messages
23
Reaction score
0
A 1260kg freight elevator is supported by a steel cable of diameter 34.9mm. It is loaded with a crowd of people collectively having a mass of 2850kg and it is descending.
What is the strain in the cable when it is brought to a stop in 0.600s?

I'm not really sure how to figure in the fact that the elevator is slowing in this equation? a little push in the right direction would be GREATLY GREATLY appreciated. thanks!
 
Physics news on Phys.org
i believe this is an impluse question, idk what the diameter has to do with anything...

\frac{dp}{dt} = F
-(1260kg + 2850kg)v = F(.6s)
solve for F and that is what i would assume "strain" means, however idk what the v would be is it given? idk...sorry...
 
you need the diameter to find the cross-sectional area of the cable. i understand all that, but i need the strain when it is slowing. i got the strain when it was moving at a constant velocity (i think).
does anyone know how to figure this?
 
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Correct statement about a reservoir with an outlet pipe'
The answer to this question is statements (ii) and (iv) are correct. (i) This is FALSE because the speed of water in the tap is greater than speed at the water surface (ii) I don't even understand this statement. What does the "seal" part have to do with water flowing out? Won't the water still flow out through the tap until the tank is empty whether the reservoir is sealed or not? (iii) In my opinion, this statement would be correct. Increasing the gravitational potential energy of the...
Back
Top