How Far Can a Car Travel When Accelerating from 0-81 mph?

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Discussion Overview

The discussion centers on estimating the distance a car would travel while accelerating from 0 to 81 mph, given its acceleration times from 0 to 60 mph and 0 to 100 mph. The scope includes theoretical considerations of motion and the complexities of real-world acceleration behavior.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant states that the car accelerates from 0-60 mph in 8.6 seconds and from 0-100 mph in 26.1 seconds, questioning how far it would travel to reach 81 mph.
  • Another participant argues that the acceleration rates are not consistent, suggesting that the problem cannot be solved definitively with the given data and that only an estimate can be made.
  • A third participant reflects on their initial confusion regarding the concept of uniform acceleration, indicating a need for clarity in understanding the assumptions involved.
  • A participant provides an estimate of 271.37 meters to reach 81 mph, noting that this is a rough estimation due to the complexities of acceleration and aerodynamic drag.
  • One participant converts the estimated distance of 271.37 meters to approximately 890.3 feet.

Areas of Agreement / Disagreement

Participants express differing views on the ability to solve the problem definitively, with some suggesting it is unsolvable while others provide estimates. There is no consensus on the exact distance or the methodology to arrive at it.

Contextual Notes

The discussion highlights limitations in the assumptions about uniform acceleration and the effects of aerodynamic drag, which are not fully resolved within the conversation.

biggspc
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A car can accelerate 0-60 mph in 8.6 seconds and 0-100 mph in 26.1 seconds. How far (in feet) would the car have to travel in order to accelerate from 0-81 mph?
 
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The acceleration rate from 0-60 mph is different than the acceleration rate from 0-100 mph. You could assume that the rate of acceleration is inversely proportional to the final speed (linear), but that really isn't the case with cars. So, with the given data, this problem is not solvable. The best you can do is find an estimate.
 
When I was first presented with the "Equations of Motion" I clearly hadn't been listening to 'Sir' well enough and I got very cross about just this point. I just thought ":How could you possibly tell?".
It took some time to take on board the qualification 'uniform acceleration'.
 
zgozvrm said:
The acceleration rate from 0-60 mph is different than the acceleration rate from 0-100 mph. You could assume that the rate of acceleration is inversely proportional to the final speed (linear), but that really isn't the case with cars. So, with the given data, this problem is not solvable. The best you can do is find an estimate.

What would the estimate be then?
 
Averaging the acceleration yields a result of 271.37m to reach the 81mph (36.21m/s).
It is a rough estimation, given that it should take more time to get that extra 19 mph from 81 to 100 mph than the 21 mph from 60 to 81 mph. Aerodynamic drag is proportional to the speed squared.
 
BTW:
271.37 m = 890.3 ft
 

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