Solving the Jump Height Mystery: How to Calculate with Unknown Mass

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Homework Help Overview

The problem involves calculating the maximum height a sprinter could jump if all his kinetic energy is converted into gravitational potential energy, given a running speed of 10 meters per second. The challenge arises from the unknown mass of the sprinter in the kinetic energy formula.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between kinetic energy and gravitational potential energy, questioning how mass affects the calculation. One participant suggests that mass cancels out in the equations, leading to a simplified height calculation.

Discussion Status

Some participants have provided guidance on the relationship between kinetic and potential energy, suggesting that the mass does not need to be known to find the height. There is an ongoing exploration of the implications of the problem setup and the assumptions involved.

Contextual Notes

There is mention of a textbook that does not fully explain the problem, leading to questions about where to find additional resources for understanding physics concepts related to energy conversion.

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The question is:

If a sprinter running at 10 meters per second could convert his
kinetic energy into upward motion, how high could he jump?

How do I solve this if I use the KE = 1/2 mv^2

I don't know what the mass is?
 
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Imagine all of that kinetic energy converted into gravitational potential energy. If you solve for the height, I think you'll find that the mass of the sprinter cancels out.
 
So are you saying I should:

1/2 mv^2 = mgh
1/2 v^2/g=h
1/2(10^2/9.8)=5.1m

The textbook I have in no way explains this, if this is correct
where can I get other sources of help on physics
 
Yes, that's what I'm saying. I wouldn't expect your textbook to explain exactly the solution to this problem, especially if it is an exercise from there. As long as it explains about kinetic and potential energy, I wouldn't be too worried. The problem asks about an isolated "what-if" situation. What if instead of running at 10m/s, the sprinter jumped with an initial upward velocity of 10 m/s. I don't think there's anything more to read into the problem than that (which is why I don't think it's a problem if your textbook doesn't say anything about situations like this).
 
Thanks, I was searching for an answer that I would never find.
 

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