Can Final Velocity Be Higher Than Displacement? | Explained"

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Discussion Overview

The discussion revolves around whether final velocity can be numerically greater than displacement or change in position, particularly in the context of a rock thrown from a height under the influence of gravity. Participants explore the implications of comparing these two quantities, including the mathematical relationships involved.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions if final velocity can exceed displacement, using a specific example of a rock thrown from a cliff.
  • Another participant confirms that it can, providing calculations related to the motion of the rock.
  • A different participant points out that comparing final velocity (in meters per second) and displacement (in meters) directly is inappropriate due to their differing units.
  • Another comment suggests that while final velocity can be greater than average velocity, it is meaningless to compare final velocity directly to displacement.
  • One participant clarifies that the original question may involve confusion between final velocity and average velocity, noting that the average velocity is always between the maximum and minimum values unless constant.

Areas of Agreement / Disagreement

Participants express differing views on the validity of comparing final velocity and displacement, with some asserting it is possible under certain interpretations, while others emphasize the importance of unit consistency and the distinction between final and average velocity. The discussion remains unresolved regarding the appropriateness of such comparisons.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the comparison of quantities with different units and the definitions of final versus average velocity. Some mathematical steps and relationships are also not fully explored.

harujina
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Sorry if this is a dumb question but can the final velocity be higher than displacement/change in position?

For example, if a rock is thrown in the water with the acceleration of gravity on a 15.3m high cliff, can final velocity be equal to 17.32m/s or is that incorrect?
 
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Of course it can! I'll quickly verify your answer.

s=ut+1/2at^2
0=-4.9t^2+15.3
t = 1.77

v=u+at
= 0-9.8x1.77
= -17.35m/s
 
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For your information, you cannot directly compare values with different units. The velocity is in meters per second and the height is in meters, so it doesn't make sense to say one is larger than the other. For example, 17.32 m/s is 0.02887 m/minute. It's the same velocity, but now the number is smaller than the number in the height.
 
since the acceleration of gravity is 9.8m/sec/sec, you can calculate the distance at which the vertical freefall distance in meters equals the velocity in meters/sec. It is meaningless though.
 
Khashishi said:
For your information, you cannot directly compare values with different units.

I think the OP is asking about the final velocity and the average velocity (total distance/total time).

Of course the final velocity can be bigger than the average. The average of any set of numbers is always somewhere in between the biggest and smallest numbers, unless all the numbers are the same (which would mean the velocity was constant).
 

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