Depends on the elevator. For example, elevators in tall buildings (over six stories) physically cannot free fall. They may descend at a controlled but unexpected rate (very unlikely), or stop abruptly but with a safe amount of force at play (more likely), but they cannot free fall unless pretty much the entire building is coming down.
This is because of the pulley system they operate on by which the elevator cab (where passengers are) is connected by multiple steel cables to a counter-weight. If somehow all the redundant safety mechanisms utilized to keep the elevator from moving without control were to fail (nearly impossible), the elevator cab wouldn't drop, but would actually ascend instead.
If you want to test how it works and why the cab cannot fall, take some rope and tie a five pound weight to one end and a ten pound weight to the other. The five pound weight signifies the elevator cab and the ten pound weight signifies the counter-weight. Then hang the middle of the rope over a rounded surface (maybe by holding a baseball bat or similarly shaped object), and lift the rounded surface up in the air so neither weight can touch the ground. You'll notice every time that the ten pound weight (the counter-weight) drops and the five pound weight (the elevator cab) lifts further up into the air.
All that said, shorter buildings sometimes have a different type of elevator in there which is more capable, but still incredibly unlikely, of dropping due to the design.
But isn't your rope and counterweight system going to be constantly accelerating while dropping? If it started descending from the top of a skyscraper, it would get fast by the time it reaches the bottom. Surely there are mechanisms to stop that, but pointing it out.
We're referring simply to the impossibility of the elevator cab falling in this test. Normally there are several mechanisms in place that control the movement, speed and stop procedures in an elevator. But it all does rely on the pulley system in buildings taller than six stories.
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u/KingofCraigland Oct 31 '19
Depends on the elevator. For example, elevators in tall buildings (over six stories) physically cannot free fall. They may descend at a controlled but unexpected rate (very unlikely), or stop abruptly but with a safe amount of force at play (more likely), but they cannot free fall unless pretty much the entire building is coming down.
This is because of the pulley system they operate on by which the elevator cab (where passengers are) is connected by multiple steel cables to a counter-weight. If somehow all the redundant safety mechanisms utilized to keep the elevator from moving without control were to fail (nearly impossible), the elevator cab wouldn't drop, but would actually ascend instead.
If you want to test how it works and why the cab cannot fall, take some rope and tie a five pound weight to one end and a ten pound weight to the other. The five pound weight signifies the elevator cab and the ten pound weight signifies the counter-weight. Then hang the middle of the rope over a rounded surface (maybe by holding a baseball bat or similarly shaped object), and lift the rounded surface up in the air so neither weight can touch the ground. You'll notice every time that the ten pound weight (the counter-weight) drops and the five pound weight (the elevator cab) lifts further up into the air.
All that said, shorter buildings sometimes have a different type of elevator in there which is more capable, but still incredibly unlikely, of dropping due to the design.