How Much Kinetic Energy to Accelerate a Proton to 0.9999c?

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To accelerate a proton to 0.9999c, the kinetic energy required can be calculated using the equation Ek=(mc^2/√(1-(v^2/c^2)))-mc^2. The mass of the proton is 1.67*10^-27 kg, leading to a rest energy of approximately 1.5*10^-10 J. The calculated kinetic energy is reported as 1.48*10^-8 J, but this value is questioned as potentially incorrect. Another calculation yields a kinetic energy of 1.047*10^-8 J, prompting discussions on the proper application of the Lorentz factor and the significance of the term (1.9999*10^-4). Clarification on the calculations and methodology is sought to ensure accuracy in determining the kinetic energy.
StillLearningToronto
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Question:

Calculate the kinetic energy required to accelerate a single proton from rest position to 0.9999c. The mass of the proton is 1.67*10^-27 kg.

Equations Used:
Ek=(mc^2/√ 1-(v^2/c^2))-mc^2

Attempt at the problem:

Ek=(1.67*10^-27kg)(3*10^8m/s)^2/√ 1-(0.9999c^2/c^2))-1.67*10^-27kg)(3*10^8m/s)^2
Ek=(1.5*10^-10/0.01)-1.5*10^-10
Ek= 1.48*10^-8

(sorry if its jumbled, I am used to writing it out in my equation editor)

I'm not fairly confident on this answer because I have found different answers online saying it was correct.

Just looking for someone to verify this, or at least point me in the right direction,
Cheers xx
 
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I didn't check your arithmetic, but an answer like "Ek= 1.48*10^-8" can never be right. Are you sure you aren't forgetting something? :oldtongue:
 
JoePhysics said:
I didn't check your arithmetic, but an answer like "Ek= 1.48*10^-8" can never be right. Are you sure you aren't forgetting something? :oldtongue:
Im very positive I am missing something.

This is what i found online:

Ekrest = mc2
Ekrest = (1.67*10^-27)(c)2
Ekrest = 1.5*10^-10

Ek= (1.5*10^-10)/√(1.9999*10^-4)-(1.5*10^-10)
EK=1.047*10^-8J

But i have NO idea how they got (1.9999*10^-4)
 
StillLearningToronto said:
But i have NO idea how they got (1.9999*10^-4)

Are you sure that everything is properly "squared" away?
 
Last edited:
StillLearningToronto said:
But i have NO idea how they got (1.9999*10^-4)
I too have no idea how they got this number or what it means, but their numerical answer 1.047×10-8 J agrees with what I got. So let me guide you through the steps that I took.
1. Write an expression for the total energy of the proton using the Lorentz factor γ.
2. Subtract the rest mass energy to find the kinetic energy of the proton.
3. Put in the numbers.
 
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