How Does Air Resistance Affect a Flea's Jump Height?

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Homework Help Overview

The discussion revolves around the jumping ability of fleas, specifically how air resistance affects their jump height. The original poster presents a scenario where a flea can jump to a height of 36 cm without air resistance, but only reaches 18 cm in reality due to air resistance. The problem involves calculating the flea's kinetic energy at takeoff and the fraction of that energy converted to potential energy at the peak of the jump.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the kinetic energy of the flea as it leaves the ground and how to approach the problem given the two different jump heights. There are questions about whether to use the height with or without air resistance for calculations.

Discussion Status

Some participants have provided guidance on using the height of 36 cm for the kinetic energy calculation, while others express confusion about the problem's wording and whether both parts of the question can be addressed meaningfully. There is an ongoing exploration of the implications of the two heights on the calculations.

Contextual Notes

Participants note that the problem statement does not clearly separate the two scenarios, leading to uncertainty about which height to use for the kinetic energy calculation. There is also a question about the relevance of part b) of the problem if part a) is based on the maximum height without air resistance.

Jaklynn429
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Homework Statement


Fleas have remarkable jumping ability. If a 0.50 mg flea jumps straight up, it will reach a height of 36 cm if there is no air resistance. In reality, air resistance limits the height to 18 cm.


Homework Equations


K=1/2 m*v^2



The Attempt at a Solution


I tried to use kinematics to get a delta T, and the program is still saying I am wrong! The final is tomorrow and this is a practice problem, can someone please explain how to do this! thanks!
 
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What is the problem?? Is it asking for how much energy is used up by air resistance?
 
I'm sorry! The problem wants to know:
a) what the flea's kinetic energy is as it leaves the ground?
b) at its highest point, what fraction is converted to potential energy?
 
I'm assuming "a) what the flea's kinetic energy is as it leaves the ground?" is for
"Fleas have remarkable jumping ability. If a 0.50 mg flea jumps straight up, it will reach a height of 36 cm if there is no air resistance."

and "b) at its highest point, what fraction is converted to potential energy?" is for "In reality, air resistance limits the height to 18 cm."

For a) energy is conserved. soo we pick the lowest point that has a gratational potential of zero. so we can use this

\frac{1}{2}mv^2=mgh
 
Here is my problem though...the statement doesn't separate those two things. The problem reads exactly this: "Fleas have remarkable jumping ability. If a 0.50 mg flea jumps straight up, it will each a height of 36 cm if there is no air resistance. In reality, air resistance limits the height to 18 cm."
a) what is the flea's kinetic energy as it leaves the ground?

That's my issue, I don't know whether to use the 36 or the 18.
 
Jaklynn429 said:
Here is my problem though...the statement doesn't separate those two things. The problem reads exactly this: "Fleas have remarkable jumping ability. If a 0.50 mg flea jumps straight up, it will each a height of 36 cm if there is no air resistance. In reality, air resistance limits the height to 18 cm."
a) what is the flea's kinetic energy as it leaves the ground?

That's my issue, I don't know whether to use the 36 or the 18.

You use 36. That's what the problem is telling you when it says if ...
 
Is there even a part b)? it would be pointless if you use point 36 for part b) because it would be 100%, of course.
 

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