How many feet does a 700 lb object take to stop?

  • Context: High School 
  • Thread starter Thread starter logan97
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Discussion Overview

The discussion revolves around the stopping distance of a 700 lb object at various speeds (20 mph, 30 mph, 40 mph), specifically in the context of a motorized vehicle. Participants explore the factors influencing stopping distance, including friction and braking mechanisms.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Homework-related

Main Points Raised

  • One participant questions the stopping distance without additional information about the stopping mechanism, suggesting that friction is a crucial factor.
  • Another participant mentions the concept of an "Immovable Object," implying that stopping distance can be zero under certain hypothetical conditions.
  • A suggestion is made to refer to institutional resources, like the Department of Transportation, for established guidelines on stopping distances based on vehicle weight and conditions.
  • A participant shares a personal anecdote related to learning about stopping distances, indicating that there are established formulas and resources available online for this information.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of additional information to determine stopping distance, with some emphasizing the importance of friction and braking systems while others suggest looking up established resources. No consensus is reached on a specific stopping distance.

Contextual Notes

The discussion highlights the dependence on various factors such as vehicle type, weather conditions, and tire types, which are not fully explored in the thread.

logan97
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hope I am in the right forum?

how many feet does a 700 lb object take to stop? @ 20 mph, 30 mph, 40 mph ?
 
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Zero...If it hits the proverbial Immovable Object.
Otherwise you need to know something about what's stopping the object, like friction.
 
schip666! said:
Zero...If it hits the proverbial Immovable Object.
Otherwise you need to know something about what's stopping the object, like friction.


sorry not enough info. It would be brakes on a 4 wheeler motorized vehicle.
 
To point you in the right directions, I am sure there are institutions (Department of Transportation?) that have "rules of thumb" charts about stopping distances for certain kinds of vehicles of certain weight in certain weather conditions with certain types of tires.

Maybe someone else can point you to a source or you can see if Google turns up anything.
 
This brings up foul memories of how I almost failed my driver's-ed class due to a poorly constructed question about using the stopping distance formula which had been pounded into us by our autocratic (pun intended) teacher...

OK. It's been 45 years. I'm over it and can now just google "automobile stopping distance" to find this handy explanation and chart:

http://www.csgnetwork.com/stopdistinfo.html
 

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