- #1
Miran97
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Hi!
The kinetic formula are EK=1/2*m*v^2. But how do we find it?
The kinetic formula are EK=1/2*m*v^2. But how do we find it?
The Power of Kinetic Energy to the EK=1/2*m*v^2 Formula
- Context: High School
- Thread starter Miran97
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Discussion Overview
The discussion revolves around the kinetic energy formula EK=1/2*m*v^2, specifically focusing on how this formula is derived and the underlying concepts related to it. Participants explore the relationship between work, force, and acceleration in the context of kinetic energy.
Discussion Character
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- Some participants inquire about the derivation of the kinetic energy formula, suggesting that the original poster (OP) may be seeking clarification on this topic.
- One participant provides a derivation based on the work-energy principle, explaining how work done on an object relates to its kinetic energy through the relationship W = F*d and the equations of motion.
- There is a suggestion that understanding the OP's actual question is crucial for providing a meaningful explanation, highlighting the challenges in communication within physics discussions.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the OP's intended question, indicating that multiple interpretations of the inquiry exist. The discussion remains somewhat unresolved regarding the clarity of the OP's original intent.
Contextual Notes
The discussion reflects varying levels of understanding and assumptions about the derivation process, as well as the importance of context in addressing questions related to physics concepts.
- #2
Doc Al
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Looks like you already found it!
What do you mean? (How you would find the kinetic energy in a particular problem will depend on the details of that problem.)
What do you mean? (How you would find the kinetic energy in a particular problem will depend on the details of that problem.)
- #3
lep11
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Maybe he/she meant to ask how the formula is derived.
- #4
K^2
Science Advisor
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The simplest derivation is to consider how much work is done to accelerate an object to velocity v. Let's say we use constant force to accelerate the object over some distance d.
F = ma -> a = F/m (From Newton's 2nd)
W = F*d (From definition of work.)
v² = 2*a*d (Let us know if you need help deriving this one, but you should have seen it.)
Putting it all together.
v² = 2*d*a = 2*d*(F/m) = 2*(d*F)/m = 2*W/m
W = (m*v²)/2
So the amount of work required to accelerate (or decelerate, for that matter) an object of mass m to velocity v is (1/2)*m*v². Hence the Kinetic Energy.
F = ma -> a = F/m (From Newton's 2nd)
W = F*d (From definition of work.)
v² = 2*a*d (Let us know if you need help deriving this one, but you should have seen it.)
Putting it all together.
v² = 2*d*a = 2*d*(F/m) = 2*(d*F)/m = 2*W/m
W = (m*v²)/2
So the amount of work required to accelerate (or decelerate, for that matter) an object of mass m to velocity v is (1/2)*m*v². Hence the Kinetic Energy.
- #5
Doc Al
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Anyone else want to guess what the OP's real question was? 
- #6
K^2
Science Advisor
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I've always found that to be the real challenge of explaining physics to someone. Once you understand what it is that the person actually wants to know or doesn't understand, explaining it is easy.Doc Al said:Anyone else want to guess what the OP's real question was?
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