Modern Physics I: Find time from energy

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Homework Help Overview

The problem involves a particle with a specified rest energy and total energy, tasked with finding the time required for it to travel a distance of four light-years from Earth. The context is rooted in modern physics, particularly in the realms of relativistic energy and motion.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss using the rest energy and total energy to calculate kinetic energy, and then using velocity to determine travel time. There is also mention of keeping calculations in terms of the speed of light to simplify conversions.

Discussion Status

Some participants have shared their calculations and results, seeking confirmation on their reasoning and outcomes. There is an ongoing exploration of different approaches to the problem, with no explicit consensus reached yet.

Contextual Notes

Participants are working under the constraints of the problem's parameters, including the specific energies given and the distance to the star. There is an emphasis on ensuring the calculations align with relativistic principles.

maherelharake
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Homework Statement


A particle with a rest energy of 2400 MeV has an energy of 15 GeB (15x10^9 eV). Find the time in Earth's frame of reference necessary for this particle to travel from Earth to a star four light-years distant.


Homework Equations





The Attempt at a Solution



I thought about using the rest energy and total energy to find the Kinetic Energy. After that I used the velocity I found and used that to find the time. Is this a good start?
 
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maherelharake said:

Homework Statement


A particle with a rest energy of 2400 MeV has an energy of 15 GeB (15x10^9 eV). Find the time in Earth's frame of reference necessary for this particle to travel from Earth to a star four light-years distant.


Homework Equations





The Attempt at a Solution



I thought about using the rest energy and total energy to find the Kinetic Energy. After that I used the velocity I found and used that to find the time. Is this a good start?

That's how I would start it. You might also be able to keep things in terms of c, since the distance is in terms of c. That way you don't need to convert back and forth from m/s.
 
Ok thanks. I tried to work it out and this is what I got. I ended up getting a value of 1.26E10 eV for kinetic energy. Using that, I got the ratio v/c to equal .987. I used that to get a time of 4.05 light years for the answer. Any thoughts? Thanks in advance.
 
I worked on this problem again today, but couldn't come up with any other way to think about it. If anyone can confirm my above thinking, I will be appreciative.
 

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